They were meant to be part of a cunning disguise to elude capture, but the fake beards worn by a pair of robbers in Italy proved to be their downfall.
The bearded bandits were identified from traces of DNA that they left on the beards during a bank raid in Paderno Dugnano near Milan.
The genetic traces enabled police to match the suspects - a 40-year-old Italian and his accomplice, a 60-year-old man from Serbia - with records on a national data base.
The two men donned the beards while robbing a branch of the Bank of Brescia in February 2014.
Armed with pistols, they locked the bank's employees in a room within the branch and then forced the manager to open the safe, from which they took 50,000 ($83,370) in cash.
The robbery went off without a hitch - but the raiders made the fatal error of dumping the beards as they made their getaway.
Security camera footage confirmed the findings of the DNA tests, enabling police to identify the two culprits. They were arrested, charged with armed robbery and remanded in custody.
They had been convicted of robberies in the past and were described by police as "serial offenders".
The DNA analysis was carried out by forensic police based in Parma, south of Milan.