More than £10,000 was stolen during a robbery at a business in Thetford.
A man entered the premises, in Market Place, at about 8am on Monday, April 10 and threatened an employee before demanding money.
More than £10,000 was taken from the safe and he fled the scene.
The member of staff was uninjured.
A man, aged in his 20s and from the Thetford area, was arrested on suspicion of drug offences, possession of a knife in a public place and robbery following a stop-search in the town.
He has been released from custody but remains under investigation.
Officers would like to speak to anyone who may have witnessed the incident or noticed a man acting suspiciously in the area. Those with information should call Thetford CID on 101.