Is the National DNA Database really such a bad thing?

In the latest in our series of Friday features, we unlock another of the secrets in the scientific world with the help of lecturers at UCO’s degree partners at Huddersfield University.

Graham Williams, Lecturer in Forensic Science at the University of Huddersfield’s School of Applied Sciences, discusses the use of DNA sampling in criminal cases

The National DNA Database (NDNAD) is often in the news both as a friend and as an enemy.

Everyone sings its praises when it is used to catch a murderer or rapist, but at the same time it is frequently vilified as an infringement of our privacy and civil liberties.

What is the database? A DNA sample can be taken from an individual or from a body fluid stain left behind at the scene of the crime. It then undergoes a DNA profiling process and a DNA profile is produced. This DNA profile is represented as a string of 20 numbers. The DNA profile is then loaded on to the database and is compared with other DNA profiles also held.

If all 20 numbers match that of another DNA profile, then a match report is generated.

Under the Police and Criminal Evidence (PACE) Act, anyone who is arrested for a recordable offence has to have their DNA sample taken.

Simply put, if you are arrested for an offence which will result in you getting a criminal record, then your DNA sample will be taken.

Your identification will be verified and a record is made on the Police National Computer (PNC). This record will contain all your personal details.

Your DNA sample is then sent to a DNA profiling laboratory, usually a part of a Forensic Science Laboratory, and a DNA profile is produced.

This DNA profile is assigned a unique identification number and then loaded on to the database.

The unique identification number is also sent to the police force, where it is then entered on to your record on the PNC. This means that the DNA database does not actually hold any personal information relating to the arrested individual.

What happens is that the match report generated only indicates the unique identification number.

The relevant force then has to take that number and look it up on the PNC in order to identify the person. This has resulted in a number of high profile arrests and convictions. Without the database, the arrest of Ronald Castree for a relatively trivial offence would not have resulted in his conviction for murder of Lesley Molseed 30 years ago.

Without the database, the Metropolitan Police would not have determined the presence of a serial rapist operating in London, thus enabling the clues to be pooled together and resulting in the conviction of Antoni Imiela, also known as “The M25 Rapist”.

So are the critics of the database justified? At present, I would say they are wrong. In my opinion, the value of the database far exceeds any perceived disadvantages.

However, note I say “at present”.

At the moment, both the DNA sample and the DNA profile are retained. The DNA profile is an innocuous string of numbers, which tells us nothing about the individual that cannot be obtained from the PNC. The DNA sample, however, is a different matter. It is possible to go back to the sample and carry out further tests, which may then identify characteristics of that individual, such as hair colour, eye colour and any disorders they may be suffering from.

If that were to happen, then I would stand firmly on the side of the critics and say that the database is an infringement of our civil liberties. At the moment, that is not the case.

I read, earlier this year, of the two men from Sheffield who successfully had their DNA profile removed from the database. This was heralded as a significant victory for privacy.

Reading this, I thought why was this a victory for privacy? Removing the DNA profile alone does absolutely nothing to reduce privacy. As I said, the DNA profile is linked to the PNC. It is the PNC which holds the personal information. Removing the DNA profile does not remove the information held on the PNC. Without the PNC, the DNA profile is only a string of numbers. I felt that the supporters of privacy went after the wrong target.

I suggest a compromise. As stated, I feel that the path for future abuse lies with the DNA sample and not the DNA profile.

The DNA sample should be retained along with the DNA profile; however, if someone’s arrest was not followed through or was found to be not guilty, then the DNA sample should be destroyed.

The DNA profile should be retained. This allows the database to function as it should, but it would not be open to any future abuse.

You may think we are increasingly living in a Big Brother state, but at this moment, the National DNA Database is an easy target and a scapegoat.