Networked Knowledge - Media Report

This version of the report has been prepared by: Dr Robert N Moles

DNA Homepage
Article on UK miscarriage of justice cases
Article on Australian miscarriage of justice cases
Article on USA miscarriage of justice cases

World Police Medical Officers Conference, Sydney 2002 “Where  Did  I  Leave  My  DNA?”

18 March 2002 N R Cowdery QC, Director of Public Prosecutions, NSW, Australia, President, International Association of Prosecutors

Abstract:

DNA technology has a significant role to play in the administration of criminal justice. But it must be acknowledged that, while it is an increasingly important tool in criminal investigation, it is not a “magic marker” identifying guilty persons. Its true contribution must be kept in perspective. The establishment of a national DNA database is the aim of many national governments and such a reference source will enable matches to be made more efficiently. In Australia there are some obstacles yet to be cleared to enable this facility to operate effectively; and even when it is operating, the principles of proof will still need to be observed in all cases in which DNA evidence is used where the liberty of the subject is in jeopardy.

Introduction

I am very conscious of the fact that I am addressing a gathering of people with far greater knowledge and experience of things scientific than I possess. I am a prosecutor. I suppose there is some science in the way that I work, too; but it is not as precise and certain as the physical sciences and there is perhaps more art involved than science. The worlds of prosecutors and scientists do, however, intersect at times in the criminal justice process. The sciences that you apply at those times become known as forensic sciences. (It is a matter of some distress to me, as an English language speaker, to note that the theme of this conference is “Forensics in the 21st Century – Australia Meeting the Challenge”. I am a full-time forensic person – you are part-time. The word “forensic” comes from the Latin “forum” and means related to the courts. If we were concerned only with forensics we would be talking this week about court procedure. Forensic science is what we are concerned with here – but I accept that this battle for linguistic precision has probably been lost.)

One of the sciences which becomes forensic more often than not is the technology of DNA and it is that subject that I have been asked to address today – particularly matters associated with the creation and operation of a national DNA database. I do so from the point of view of a lawyer and in the Australian context. I am not qualified to explore too deeply the science and, importantly, the mathematics of DNA. (I am a lawyer because I was not very good at maths and science and my abilities in those fields have not improved significantly with age.) There are many in the audience who are eminently qualified to talk to you about the science. Virtually everything that I say is subject to correction by those who know better. Other people’s DNA is important to lawyers. To a prosecutor, DNA evidence may mean the difference between an arguable case and a case against which there is no reasonably sustainable argument. To a defence lawyer, it may spell grim news – or it may mean complete exoneration for the client. Whichever side of a case the lawyer is on, the issues surrounding the sources and use of such evidence need to be understood. They are also important to the scientists who provide the evidence with which we work.

DNA

First, a brief, incomplete (but hopefully accurate, so far as it goes), lawyer’s reminder of what we are talking about. This is an audience drawn from different disciplines and not everyone may be an expert on DNA. The fictitious Horace Rumpole was an expert on bloodstains (following his sterling work for the defence in the Penge Bungalow Murders case, of course). He was able to draw upon a long record of the use of biological material in criminal investigations. Indeed, there are records of bloodstains being used for forensic purposes as early as 384 AD. Only since about 1985 have we been able to benefit from DNA profiling. James Watson and Francis Crick modelled the structure of DNA in 1953 and were awarded the Nobel Prize in 1962.

Deoxyribonucleic acid (DNA) has been described as the blueprint for life. It is the fundamental natural material that determines the genetic characteristics of all life forms and is made up of two strands of alternating units of a sugar, phosphate and bases, twisted into a spiral. It codes for the make-up of the animal or plant in which it is contained, the code being in the bases where the links occur between the two strands of DNA. There are four different kinds of bases and the proportions of each of the bases and the order in which they are arranged code for each species of living thing. (A section of DNA, containing a particular sequence of bases, may be described as a gene. Chromosomes are larger groups of genes, nearly 100,000 in each case.) The sequence of the bases along the strands of DNA is code that we can read and sections of the strands can be replicated for examination.

For humans, DNA is found in all cells in the body which contain a nucleus – red blood cells are excluded. There is nuclear DNA, inherited from the father and the mother in random combinations and only identical twins have the same nuclear DNA. There is also mitochondrial DNA, in the mitochondria of nucleated cells, which is a copy of the mother’s DNA. It is more expensive to analyse and the results may not be as conclusive. (The first conviction on the basis of mitochondrial DNA was in the USA in 1996 – Paul Ware was convicted of the rape and murder of a young girl after testing of a hair found on the girl). The DNA in one individual is identical in every cell. It has been estimated that over 99% of the DNA in one human is identical with that of every other human, so the remaining less than 1% gives us the individual differences that may be detected. Between the sections of DNA (the genes) which operate for specific functions (eg genetic information about race, hair colour, eye colour, height or predisposition to disease) there is so-called “junk” DNA, base sequences that are of no identifiable functional use. This “junk” DNA was identified in 1980 and was found to be extremely variable between individuals. DNA analysis uses this “junk” DNA, which consists of sections of repeating short sequences, for comparison purposes, usually (at least in the Profiler Plus system that is used in Australia) with 9 sites (or loci) selected plus the sex indicator.

The statistics of these comparisons and the probability calculations derived from them are the part of all this that is ultimately of significance to the forensic work done by lawyers in the identification of individuals. We talk of “match probability”, meaning the probability that a randomly selected, unknown, unrelated person would have the same DNA profile as the suspect. (The way in which those calculations are done and the factors that bear upon them I leave to others.) We are not very protective of our DNA – we carelessly leave it everywhere. That is why lawyers become so excited about it. It is in our blood (the white cells only), semen, mucous secretions, hair roots, skin, faeces, urine, vomit, bone marrow and in cells in saliva, sweat and tears. We leave sweat and skin cells all over the place – on just about everything we touch and wear next to our skin, including other people’s hands when we shake them, car steering wheels, doorknobs, knife handles and guns. We leave saliva on masks, balaclavas, stamps, envelopes, chewing gum, the rims of drinking glasses and cigarette butts. Offenders may leave DNA on or in victims – and the victims may pass their DNA to the offenders or the offenders’ clothing or possessions. If we bleed, spit, ejaculate or otherwise make a cellular deposit onto something, we leave our signature – and a signature that cannot be forged. We leave a DNA trail wherever we go – and it is our trail, not just a trail like somebody else’s (unless we have an identical twin) – and lawyers (especially criminal lawyers) love to follow trails. Nevertheless, the ultimate question remains an appreciation of where the trail has led us – because that very carelessness about protecting our DNA may enable it to be found on things and at places with which we have only an innocent connection.

All trails are not equally clear. Our experience here shows that blood has a 90% chance of producing a DNA profile; saliva on a cigarette butt 67% but on a balaclava only 43%; sweat on the handle of a weapon 17%; fallen hair (with dead roots) 25% but plucked hair much higher. These are the results that can be achieved from samples on items found at crime scenes. Issues of concern to many – and of interest to lawyers especially – are: with what should those results be compared? And: what conclusion should be drawn from any such comparison? Although we are so careless about losing our DNA, we are usually much more careful about giving it away. It is a part of us – it is private – it is something that we should not ordinarily be forced to part with. But many of us are. It is exceptionally easy to give away, too – even less of a process than giving fingerprints. A cotton swab rolled around the inside of the cheek is all that is required and is the most common (but not the only) means adopted in Australia. Our nervousness about voluntarily parting with our DNA is exemplified by the current opposition by police unions around this country to there being created a DNA database of police officers. The reasoning behind the proposal, which emanated from Tasmania, is that such a database could be used to eliminate police from samples collected at contaminated crime scenes. Because, of course, as well as enabling extremely persuasive inferences to be drawn from matches of DNA as between person and crime scene sample, DNA technology also enables suspects or others to be conclusively excluded from further consideration. It is a tool that may point to guilt – but it may also establish innocence with even more certainty.

The police have objected on the rather spurious (to my mind) grounds of equality – why are only police being asked to contribute and not others who visit crime scenes, like ambulance officers and firemen? – and privacy – the prospect of the DNA being used for means other than identification: but these concerns could be overcome by legislative and administrative controls such as already exist for other DNA collection. In the USA the FBI has proposed that the National DNA Index System be expanded to permit it to take samples from suspected terrorists, including the detainees being held in Afghanistan and Cuba. Facing the prospect of having to release these people without, in many cases, having established their identity, the US wants to retain a record of them to compare against any crime scene samples and the like that may in future be connected with terrorist acts. Even if primary offenders are identified, links may be able to be made to accomplices who have not been apprehended. This has caused another flurry of activity among civil liberties groups.

Forensic use of DNA

The first use of DNA evidence in criminal investigation was in England in 1985/6 and it produced some interesting consequences. Two women had been raped and killed and the police believed that one person was responsible for both homicides. A suspect confessed to one, but denied the other. Professor Alec Jeffreys of Leicester University, who had been researching DNA and had discovered in 1984 a method of identifying individuals from DNA, tested some crime scene samples which showed that the killings were in fact likely to have been committed by the same person. He tested the suspect who had confessed – but there was no match. There was a mass screening of nearby villagers (as we have had in Wee Waa in NSW in the investigation of a rape) and the offender was discovered after it became known a few years later that he had persuaded a friend to substitute his blood. Colin Pitchfork was ultimately sentenced to two life terms. The UK has conducted around 150 mass screenings, I understand, in respect of homicides and rapes. There have been over 75 matches. As at mid-2001 there had been 20 matches for murders from mass screening and 33 for sex offences. Those matches have enabled some suspects to be excluded and investigations to continue along more productive paths.

The first person to be convicted of a crime – rape – directly on the basis of DNA evidence was Robert Melias, also in the UK, in 1987. The first person to have a conviction overturned on the basis of DNA evidence was Gary Dotson in the USA in 1989. He had served 8 years of a sentence of 25-50 years for rape. The first Australian case using DNA evidence was in 1989 in Canberra. There were charges of sexual assault of a woman against one Desmond Applebee, who at first said that he wasn’t there at all. DNA profiling from blood and semen on the victim’s clothes showed that there was one chance in 165 million that it was not his. After a period of attacking the police investigation, he changed his defence to one of consent by the woman. The jury having heard evidence at first of his rather shaky alibi, then his attack on the police investigation, then having heard that, well, he was actually there but she consented, had little difficulty ultimately in convicting him.

A few months later in 1989 in Melbourne a serial rapist, George Kaufman, pleaded guilty to a number of offences after DNA matching established that he was probably the perpetrator. His DNA was initially identified from samples given by his wife and daughter – later he provided a blood sample himself and ultimately he confessed. The use of DNA evidence in criminal cases has now become a daily phenomenon in a great many countries the world over. I have mentioned the Wee Waa rape case where in 2000 about 600 male inhabitants of the small town between certain ages volunteered, on request, to provide samples for DNA testing. (Twelve eligible men, including a solicitor, refused to participate.) The offender confessed as he gave his sample (which, on later analysis, did provide a match with the crime scene). However, it should also be noted that DNA profiling of several suspects had already been undertaken at an earlier stage of the investigation and they had been excluded (with consequential benefits for them and for the course of the investigation).

Powers of DNA Evidence

From the prosecutor’s perspective, DNA evidence plays at least the following three roles in the criminal justice process.
a) Matches of DNA may enable inferences to be drawn about the involvement of individuals in the commission of offences. DNA may be found at crime scenes; it may be obtained from suspects; profiles may be obtained from a database. Comparisons, one to another, may enable inferences to be drawn about the number of offenders involved and the possible identity of those offenders. Those inferences may point powerfully to the guilt of a person accused by establishing that he or she had a personal connection with a relevant place or thing or other person.
b) Those same comparisons may also indicate, in this case with certainty, that an individual was not involved in a particular crime. That important consequence can lead and has led to individuals being excluded from investigations. There are obvious resulting benefits to the individuals concerned and also to the investigation process itself, specific individuals no longer being subjects of interest. People with criminal records may not be investigated if they can be excluded at the beginning. Alibi evidence may not need to be obtained and investigated. The “usual suspects” (of Casablanca fame) need not be rounded up as often. This may apply to hundreds of suspects a year in jurisdiction the size of NSW.
c) For similar reasons, initiatives such as the NSW Innocence Panel (and Innocence Projects in other jurisdictions, often run by law teachers and students) can assist wrongly convicted persons to demonstrate that they could not have been involved in the offences for which they were convicted. Many have been released from prison in the USA and even from death row.

Clearly, the establishment of national DNA databases can contribute to these outcomes in a more comprehensive and efficient manner than may be produced by reliance on localised information sources. Databases of DNA profiles also enable “cold hits” to be made where no other sufficient information is available. Cold hits are matches between profiles on the database and individuals not previously suspected of the crime. As items of intelligence they can clarify and direct an investigation and enable the more efficient and effective use of law enforcement resources. In a submission to a NSW Parliamentary Committee last year Dr Ross Vining, Deputy Director of the Division of Analytical Laboratories, said:
“Many studies have concluded that a small proportion of the population commits the majority of the crime in any given community. [It is also said that about 10% of those offenders commit about 30% of the crimes.] Recidivism rates are very high amongst some criminals. The UK experience has been that ‘cold links’ using DNA profiling matches have resulted in numerous cases being solved. In some cases, crime scene to offender links have resulted in guilty pleas, in other cases scene to scene matches in serious cases have resulted in more effective investigation by the police of cases with the knowledge that the crimes were committed by a serial offender. In other matters a cold link on the database has solved serious investigations where traditional investigative methods have been ineffective.”

Before comparisons of profiles can be made, however, samples need to be obtained and recorded. As early as 1989 the critics were voicing concerns. How would police (or other authorities) be able to obtain person samples? Legislation would be required. What powers would it provide? There were also some early doubts raised by cases such as Castro in New York State which raised issues about laboratory techniques and testing standards, but those issues have now been addressed satisfactorily (at least in Australia).

National DNA Databases

In England and Wales the Police and Criminal Evidence Act 1984 enabled the taking of blood samples and comparisons with databases. Later, DNA samples were added. The Act also provides for an adverse inference to be drawn from the refusal to supply a sample after appropriate steps have been taken. An amendment in 1994 enables comparisons to be made against any database held by a United Kingdom police force and the world’s first DNA database commenced operations in the UK in 1995. Chief Constable Gunn of the Cambridgeshire Constabulary has described DNA as:
“the most significant advance in the use of forensic science by police since the advent of fingerprints 100 years ago. It has brought leading edge technology into the fight against crime … It not only helps to convict those who have committed crime, it can positively acquit the innocent. The use of DNA has greatly enhanced our ability to identify suspects for crime, reducing the cost of investigations, particularly in serious crime. The growing effectiveness of the National DNA Database will be a significant deterrence against those who commit crime.”

In the 5 year period from mid-1995 to mid-2000 in the UK the database received 817,448 profiles from suspects. In that period there were 77,522 matches of person to crime scene and 11,073 matches of crime scene to crime scene. The UK database produces a cold hit rate of 18%, which compares favourably with a 10% rate for fingerprints. New Zealand has had legislation to enable the creation of a national database since 1991 (under the Criminal Investigations (Blood Samples) Act 1991) – persons convicted of certain prescribed offences may be ordered by a court to provide a blood sample for a database and volunteers may also be recorded. Further legislation in 1995 created an operational DNA database and as of the middle of last year there were about 10,000 samples on it. The hit rate for a crime scene sample is about 30% - matching either a person or another crime scene sample.

In Canada the Criminal Code enables samples to be taken by warrant from persons suspected of certain designated offences and by order from persons convicted of certain offences. The DNA Identification Act 1998 establishes a national DNA database with a crime scene index and an offenders index. The FBI National DNA Index System in the USA was set up in 1998. It enables city, county, state and federal law enforcement agencies to compare DNA profiles electronically. Australia has not moved quite so smoothly, as is usually the case when action has to be taken at State or Territory and Commonwealth levels. Typically, every jurisdiction has reacted in a different way; but it has been accepted that a national approach is required. In 1997 the police services endorsed the establishment of a national criminal DNA database and formed a working party to implement it. The intention is to establish a national DNA database under the auspices of a federal initiative known as the Commonwealth CrimTrac Agency which was established in 2000 – but there is still a long way to go. It is instructive to look at the way in which Australian legislation has developed.

In 1990 the Standing Committee of Attorneys General established the Model Criminal Code Officers Committee (MCCOC) which was to include in its tasks the formulation of a Model Forensic Procedures Bill for Australia. It was eventually agreed upon (after a number of drafts and many consultations) in 2000. Nevertheless, it has not yet been adopted completely by all jurisdictions. The Bill provides, amongst other things, for a national DNA database.

The Model Bill also:
gives power to request or require samples from suspects, convicted persons and volunteers;
prescribes procedures, including safeguards for the subject of the testing;
makes evidentiary rules for improperly obtained evidence; and
establishes a scheme for interstate jurisdiction.

It distinguishes between intimate and non-intimate procedures. Intimate procedures involve the taking of blood, pubic hair, a dental impression, a sample of saliva by buccal (mouth) swab or anything involving the genital or anal areas, buttocks or female breasts. These procedures may be carried out only with informed consent or by judicial order. Non-intimate procedures, with lesser safeguards for the subject, are any examination of parts of the body other than the intimate areas, taking a hair from other than the pubic area, taking a sample from or from under a finger or toe nail and taking a print of a finger, hand, toe or foot. Informed consent overcomes all barriers. If it is not given, a judicial order (or order by a police officer in certain circumstances) must be obtained.

The DNA database envisioned by the Model Bill is to have the following seven categories of indexes of samples:
crime scene samples;
missing persons or their relatives;
unknown deceased persons;
serious offenders;
volunteers for unlimited purposes (including known deceased persons);
volunteers for limited purposes; and
suspects.

Rules are established as to which index may be matched against another and arrangements are made in certain circumstances for sharing information across State and Territory borders.

Safeguards are provided for privacy, having certain procedures carried out by persons of the same sex, videotaping procedures, the presence of an interview friend for a child or incapable person, prohibiting cruel, inhuman or degrading treatment and providing part of the sample to the person for his/her own analysis. There are also rules for the exclusion from evidence or the admission of samples improperly obtained. In 1998 the Commonwealth committed itself to CrimTrac and, as I have said, the Agency was established in 2000. On 20 June 2001 the National Criminal Investigative DNA Database (NCIDD) became operational, but without access to records from multiple jurisdictions it does not add much value. CrimTrac is intended to include NCIDD, a National Automated Fingerprint Identification System, a National Child Sex Offenders Register and rapid access to national operational policing data.

Legislation

Victoria was the first Australian jurisdiction to legislate for a DNA database in 1997, three years before the MCCOC Model Bill was settled. After three years’ operation the database had over 6,000 profiles on it and there had been 1,567 matches, including 357 linking person to crime scene and 210 crime scene to crime scene. In South Australia now 30% of crime scene samples match another crime scene and almost 25% of offender profiles have matched an unsolved crime. In NSW the Police have identified a number of uses for DNA testing in their “Future Directions 2001-2005” plan:
identifying or excluding suspects by comparison with samples found at crime scenes;
doing so by the appropriate use of mass screenings;
linking seemingly unrelated crimes by comparing profiles found at different crime scenes; and
targeting some high volume crime areas with traditionally low clearance rates which become higher when DNA profiling is used.

The Crimes (Forensic Procedures) Act was passed in 2000. It substantially follows the Model Bill, but puts buccal swabs in their own, third category (although the rules that apply to them are virtually the same as those for intimate samples). In addition to the sorts of matters referred to already, the Act provides that all the material used in these analyses must be destroyed after a suspect is acquitted, a conviction is quashed, no conviction is recorded, proceedings have not been instituted for 12 months, proceedings have been discontinued or the evidence is ruled inadmissible. DNA profiles may be retained on an electronic database and the operation of such a database is regulated. For example, DNA profiles taken from suspects and convicted serious indictable offenders may be matched against the crime scene index; whereas profiles from volunteers for limited purposes may only be matched against the crime scene in respect of which the voluntary sample was given. The crime scene index may be matched against other databases in order to identify deceased or missing persons. All jurisdictions in Australia have now enacted legislation which falls loosely into three categories:
a) those closely following the Model Bill (NSW, the Commonwealth and the ACT);
b) those that follow it in some respects (Tasmania, Victoria and South Australia); and
c) those that do not follow it at all (Queensland, the Northern Territory and Western Australia).

These differences create inconsistencies in the description of the offences for which samples may be taken, the definitions of intimate and non-intimate samples, the nature of samples able to be taken, the power of police to take samples, the rules for matching samples and the retention or destruction of samples and records. These inconsistencies have the potential to cause evidentiary problems if and when CrimTrac is under way and samples are matched across State and Territory borders. It may be useful to describe broadly the scheme finally established by the legislation in NSW.

New South Wales

The Crimes (Forensic Procedures) Act 2000 commenced operation on 1 January 2001. It establishes a scheme for taking forensic samples from suspects, persons convicted of serious indictable offences and volunteers. It provides for the use and destruction of that material and for its comparison with other material, including that on a national DNA database. Suspects are defined to include persons who have not been arrested or charged (and are therefore not in police custody). There are three categories of procedures: non-intimate, intimate and buccal swabs (treated, in effect, as an intimate procedure). These descriptions are consistent with the MCCOC Model Bill. Non-intimate procedures may be carried out on persons suspected of summary or indictable offences; intimate procedures and buccal swabs only on persons suspected of prescribed offences (presently limited to indictable offences).
A suspect may give informed consent to a procedure. The requirements to be followed are set out in the Act. Failing that, it may be carried out pursuant to an order of a senior police officer (for a non-intimate procedure only) or a court.
A convicted serious indictable offender is one convicted of an offence carrying a maximum penalty of 5 or more years of imprisonment. Similar requirements must be met as for suspects.
Any volunteer must give informed consent (or the informed consent of a parent or guardian or a court order in the case of a child or incapable person) and the term includes any convicted person who requests a review of the conviction (including a review assisted by the Innocence Panel).
The classes of persons who may carry out particular tests are prescribed by the Act. Some tests, such as a buccal swab, may be self-administered.
Unless a conviction is obtained and sustained, samples obtained from suspects must be destroyed.
Rules are prescribed for the matching of samples (and I referred to some of these a little earlier).
Particular provisions are made for indigenous suspects, juveniles and incapable persons.

Progress

New South Wales has been leading the charge in practical terms since the legislation commenced last year. DNA profiling has proceeded apace and a range of controls has been put in place. A DNA Oversight Committee drawn from scientific, police, legal, medical and supervisory bodies operates to monitor the processes of testing, storage, use and destruction of DNA. It is the independent custodian of the NSW DNA database and audits the operation of the laboratory. The laboratory, part of the Health Department, has been expanded and refurbished and additional equipment installed and staff recruited. An Inter-Departmental Committee meets regularly to address operational issues arising from the implementation of the Act.

In NSW we presently have a total of about 7,800 prisoners serving sentences for all types of offences (including about 650 DNA-eligible periodic detention prisoners). To the end of October 2001 (that is, in the course of the first 10 months of operation) 7,207 samples had been received for testing from convicted offenders (prisoners) and 1,134 from suspects. There were 1,028 from appellants, victims and volunteers. The total was 9,369. DNA profiling had been completed on 7,964 of those samples and approximately 3,800 had been uploaded to the CrimTrac database. (NSW was the only State to have uploaded to CrimTrac at that stage.) Now there are over 8,000 NSW profiles on CrimTrac. An overall total of 13,334 DNA profiles were completed in the 10 month period, compared with 2,778 in the same period in 2000. 4,831 crime scene samples had been forwarded and profiling completed on 5,370 (including some carried over from 2000). These related to 1,760 separate cases, compared with 590 cases in the same period in 2000. Most involved deposits of semen.

The first “cold hit” in Australia was in Victoria in 1999. The DNA profile of a convicted thief was matched with blood in a car used in a burglary for which he was not previously suspected. In NSW to date 160 cold hits have been obtained, including some for very serious offences that might otherwise have gone unsolved. There have been only 3 mass screenings (Wee Waa, Kings Cross and on the north coast).

Benefits

I have said much about the potential benefits of the use of DNA profiling. All the signs in NSW point to an increasing number of database matches with a consequential improvement in crime clear-up statistics. The police assert that once 1% of the population (made up of convicted offenders) is on the database, links with crime scene samples will be expected in 30-50% of matters. That evidence will be important for investigations and for the prosecution of crime. Police say that one of the benefits of having as many criminal offenders as possible on the database arises from the fact that many serious sex offenders, if not most, start offending with less serious volume crime. Targeting these offenders early in their careers will have beneficial effects all round – in crime prevention and detection.

Issues

Nevertheless, there remain some concerns among defence lawyers in particular about the use of this technology (and it is probably healthy for the introduction of any new tools – especially those based on science – to be greeted cautiously and even with slight over-reaction to the potential downside). Some of those concerns are as follows.
It is a dangerous simplification to say, as many people do, that because a DNA match has been made, the offender has been identified and conviction will follow automatically. DNA provides a link between a person and a place or thing or another person – how that link occurred and the significance of that link in the overall case remain to be proved.
A match produces only a statistical probability of a link and that must be borne in mind – it is not an incontrovertible result.
Screening of significant parts of the population and mass screenings may do nothing more than to provide, at great financial and human rights cost, more links of more people with more scenes. Again, such links remain to be explained.
As a matter of principle, in a free society, personal information should not be taken compulsorily from citizens and stored against the possibility of future wrongdoing. There should first be evidence justifying such action.
There are implications in the procedures we are following for the presumption of innocence and the freedom from forced self-incrimination.
The right to privacy is at risk. Genetic information is being provided, sometimes under compulsion, and even if there is no present risk there is the possibility of “function creep” in the future, with the information being adapted to other purposes. This is particularly the case in those places where the sample and not just the DNA profile may be retained. Information gathered, especially by compulsion, may be abused by the unscrupulous (eg apparently governments in Iceland and Tonga have sold genetic information about their citizens to researchers without the consent of the subjects). Insurance companies may have a great interest in genetic information – but quaere whether they would be interested in profiles from “junk” DNA? (These concerns could probably be overcome by appropriately foresighted legislation.)
Some are concerned that senior police officers can make orders for the taking of samples in certain circumstances and that the protection of the intervention of an independent judicial officer is denied.
Prisoners should not be tested just because they are prisoners and might have committed other offences or might reoffend in future. They should be tested only if there are grounds for such suspicions presently existing. (For example, most murderers do not reoffend and many of them have not offended in the past, but they are top of the list of prisoners to be tested.)
There should be tighter controls on the admissibility of this evidence to ensure that prescribed procedures have been followed in all cases in which it is used. That is, discretionary admission where a formality has not been observed should be removed.

False matches will occur from time to time, especially with comparisons with large databases. There have already been false matches in the UK and in New Zealand (in the former case from the use of only a small number of loci and in the latter case probably resulting from laboratory contamination). It is particularly discriminatory against prisoners for them to be at the greatest risk of false matches, because they are the most likely members of society to be prejudiced by such results and to be unable to defend themselves successfully.

Reliance on DNA may divert resources and efforts from more traditional and effective forms of policing.

There is a risk of DNA material being planted at crime scenes (or other forms of tampering along the line of testing) or having been deposited there innocently, so room must be left for explanations to be made.

There is a risk of faulty laboratory results or contamination from faulty procedures. Even something as simple as mis-labelling may lead to false conclusions. Results of testing may be misinterpreted.

A potential volunteer who refuses to comply with a request for a sample can easily become a suspect.

Different rules in different jurisdictions may enable investigators to have access to evidence that they would not be able to rely on in their own jurisdiction.

Conclusion

There are grounds for much confidence and optimism about the benefits to crime fighting able to be provided by DNA profiling. Nevertheless, we should remain alert to possible dangers and to the protection of fundamental human rights. The end will not always justify the means, even in the protection of society from crime. If the science is pursued with competence and integrity, however, it will provide another basis for the happy marriage of science and the law in the forensic environment.

Top of Page