Fingerprints are one of the most common techniques

Fingerprints
are one of the most common techniques used by forensic examiners to work out
who was at the scene. There is a basic assumption that everybody’s fingerprints
are different, including identical twins. Even criminologists and law
enforcement officials vowed that fingerprint identification was infallible.
However, after an important development in 2004, the FBI no longer testifies
that this is true. In March 2004, a terrorist attack in Madrid, killed 191
people and injured almost 2,000. After the bombings, a single fingerprint was
found by crime scene investigators on one of the detonating devices, it was
then sent to the FBI by the Spanish Police. At the same time, several thousand
miles away, Brandon Mayfield was a lawyer in America He had previously served
in the Army. Due to his former employment and a previous arrest 20 years prior,
his fingerprints had been stored in a national database. When an FBI forensic
examiner scrutinized the print, he concluded that it belonged to Mayfield. Although
there were 20 potential matches, the expert believed the differences in the
prints were insignificant as there was more than 15 points that matched
Mayfield and the print found at the scene. Four other experts also examined the
prints and they all came to the same conclusion. Mayfield was arrested on
suspicion of involvement in the attack. He was later released from custody,
after records revealed that he had never travelled to Spain before. The Spanish
National Police announced soon after that they had matched the prints to
another man who had a long police record and also was a resident in the Spanish
capital. But how did this go so wrong? The print found at the scene was only
partial which meant there was not enough evidence to be able to make such a
confident accusation. This reduces reliability of analysing fingerprints as the
full, intact print must be found at the scene for it to be reliable. Often at a
crime scene or place of interest, full fingerprints are not found. Like stated
previously, people believe that fingerprints are completely unique and will now
take extra caution not to leave a trace behind. Partial prints are much more
common to find and if they are not reliable, then this makes it much harder to
convict as the evidence is deemed as invalid.