Clifford G. Miller, a solicitor and a former university lecturer, considers recent developments questioning the infallibility of fingerprint forensic evidence
For nearly 100 years, internationally and in the UK, 16 ridge characteristics of partial latent fingerprints found at crime scenes have been used as the standard by fingerprint examiners to compare against inked prints taken from suspects (see R v Castleton (Thomas Herbert) (1910) 3 Cr App R 74). These identifications have, in all but rare cases, been treated unquestioningly as an exact means of linking a suspect to a crime scene print.
The standard of taking 16 ridge characteristics was based on a 1912 paper published in France by M. Alphonse Bertillon (Les empreintes digitales, Archives d’anthropologie criminelle, pages 36-52).
In a 1999 Court of Appeal judgment, the then vice president of the court, Lord Justice Rose, found that:
… in recent times, the originals of the prints used by Bertillon have been examined and revealed conclusively to be forgeries. It is therefore apparent that the 16 point standard was adopted on a false basis” (Buckley, R v  EWCA Crim 1191 (30 April 1999)).
In the last decade, there have been dramatic developments calling into question the reliability of fingerprint identification of crime suspects. The scientific foundation of the fingerprint field has now come to be questioned. Latent fingerprint identifications may not be as reliable as previously assumed (see SA Cole. 2002. Suspect Identities: A History of Fingerprinting and Criminal Identification. Boston: Harvard University Press; Epstein).
Uniqueness of prints is impossible to establish scientifically. It is not possible to state with certainty that no two people have exactly the same fingerprints, nor that an individual’s fingerprints are unchanging over time. Fingerprints of genetically identical twins are closely similar but not identical. This suggests a reasonable inference is that two individuals’ fingerprints are highly unlikely to be indistinguishable. But can one determine with adequate reliability that an imperfect impression at a crime scene was made by the same finger that made an impression in a file from years before, possibly with imperfections which differ?
In October 2007, Baltimore County Circuit Judge Susan M Souder refused to allow testimony of a fingerprint analyst that a latent fingerprint was made by the defendant. It was a capital case. Judge Souder held that traditional fingerprint analysis to be “subjective, untested, unverifiable identification procedure that purports to be infallible” (State of Maryland v Bryan Rose. In the Circuit Court for Baltimore County. Case No. K06-545).
Developments in this most basic of all forensic evidence fields have often been overlooked, including in England and Wales, even though some of the most important have happened very close to home – in the 1998 trial in Scotland of David Asbury for the 1997 murder of Marion Ross. The repercussions led to The Scottish Fingerprint Inquiry, chaired by Sir Anthony Campbell. The extensive report was published on 14 December 2011 after six months of hearing evidence and considerably longer in consideration. The origin of a fingerprint – “Y7″– from the murder scene was alleged by Asbury’s defence to be that of police officer Sharon McKie. In evidence, McKie denied the print was hers and ever being at the scene. After Asbury’s conviction, McKie was prosecuted and convicted of perjury. In 2002, in consequence, Asbury’s conviction was overturned in an unopposed appeal. McKie, her family and her supporters, however, fought hard to establish her innocence. She was eventually unanimously acquitted and, in 2005, won £750,000 damages from the Scottish government.
The main conclusion of The Scottish Fingerprint Inquiry, which almost all courts internationally had not in over 100 years come to appreciate, is:
Fingerprint evidence should be recognised as opinion evidence, not fact, and those involved in the criminal justice system need to assess it as such on its merits … Examiners should discontinue reporting conclusions on identification or exclusion with a claim to 100% certainty or on any other basis suggesting that fingerprint evidence is infallible” (Scottish Fingerprint Inquiry final report, page 740).
Perhaps greater heed should have been taken of the 1999 detailed advice of the English Court of Appeal in Buckley on standards and procedures to be adopted with forensic fingerprint evidence. Lord Justice Rose in judgment also noted the concession of an expert’s testimony in cross-examination, that he “was expressing a professional opinion and not a scientific conclusion”.
Clifford G. Miller BSc ARCS is a solicitor, a former university lecturer in law, at Imperial College, London University, and a published academic on complex technical and medical evidence.