Arguably the most important advance in police work since the fingerprint, DNA profiling has only really been in general forensic use for that last two decades. The first case of DNA being used to solve a crime wasn’t until 1986. Now analysts can identify the colour of a suspect's hair from DNA and experts predict that skin colour and facial characteristics will soon be detectable.

Samples of DNA found at the crime scene are often too small to analyse. Polymerase Chain Reaction (PCR) equipment utilises the natural way DNA copies itself and amplifies it, giving criminalists replicated useable DNA strands.

This breakthrough in genetic technology has also helped crack cases that have been unsolved for years. Now, so-called ‘cold cases’ are being routinely reopened and investigated using modern forensic techniques – some dating back to the 1950s and beyond.