A fifth man has been convicted in a £40 million raid on Graff Diamonds that took place in August 2009, news outlets report.

The robbery, captured on security footage, showed employee Petra Ehnar being held at gunpoint and forced to hand over gemstone and diamond jewelry items. She was then abducted as the robbers made their escape, but unharmed.

Craig Calderwood was found guilty on charges of robbery and possession of a firearm, after four other members of the gang were convicted in summer 2010 on charges of conspiracy to rob. The leader, Aman Kassaye, was also found guilty of kidnap and firearms offences.

To date, none of the 43 pieces of jewelry have been recovered.