Mass Spectrometry; the future of the fingerprint evidence?
A new technique for identifying criminals could be in use ‘within months’ following years of development by Sheffield Hallam University. But what is it and could there be problems?
Mass Spectrometry: analysing the ridges of the fingerprints
Fingerprints on crime scenes, weapons and stolen property have been the undoing of many a criminal over the years. With evidence being corroborated by DNA, CCTV and cell-site analysis the commission of crime, for the petty criminal at least, is getting harder and harder to get away with.
The latest development in fingerprint testing could potentially take prosecution evidence to a new level. Researchers have developed a technique called ‘mass spectrometry’, which analyses traces of substances ‘on or within the ridges of the fingerprints’.
It is claimed that the technique can reveal whether the print belongs to a male of female, whether there are traces of drugs and whether a person has handled a condom, the latter claim being so specific that the brand can be identified. This is a significant leap on from the current position of simply identifying the owner of a particular print.
Certain crimes should therefore be more detectable, for example a defendant denying that he/she has handled drugs will have a far more difficult time in court if the evidence shows that drugs have been taken.
Our concern is that unless the match is so precise it will be difficult to show a direct correlation between drugs seized and drugs taken. Any given batch of drugs is likely to have differences which could, of course, be reflected in the print it leaves. However, taking the condom claim, which is clearly intended to improve the quality of evidence in rape and sexual assault cases, an item such as that will be produced in a factory with rigorous quality controls. Deviations in product are, we expect, likely to be far fewer.
That of course brings us on to the obvious question; although the test can deduce that a suspect handled a brand ‘A’ condom is it able to provide any clue as to when? What if the complainant is mistaken and actually a brand ‘B’ condom was used in the assault? Will that negate their complaint and offer a defence.
Current problems associated to fingerprint evidence
Similar problems already exist with the use of fingerprint evidence as we currently know it. Whilst a fingerprint may well show that a suspect has a link to a particular place it does not provide the date/time on which it was left at the scene. Unless mass spectrometry is able to provide a specific date and time as to when the identified substance was handled by the suspect its use will face the same limitations as current methods. Although a significant jump forward the value of the evidence it produces will be limited unless there is other corroborating evidence against a suspect.
For years DNA was seen as infallible but recent reports show that the evidence it yields is not as clear-cut as it could be. Although an admirable leap forward and one which will no doubt be refined in years to come we should exercise caution in the reliance of mass spectrometry evidence as being the smoking gun in cases.
The biggest limitation though is the database itself. A print or sample is only ever going to be effective if there is a match on a database entry. There are numerous unsolved crimes committed each year ranging from murder and rape to theft and public order. Some will naturally lend themselves to having some form of physical evidence such as DNA or fingerprint. However, even a murder case with a fingerprint on the weapon and the perpetrator’s blood on floor means nothing if that person is not on the police database.
Duncan Roberts, Solicitor