A raider threatened staff at a Preston bookmakers with a knife before stealing cash and fleeing the scene.
Police said a man went into the Betfred shop at Lane Ends on Blackpool Road, Ashton, at about 9.30am on Sunday.
He threatened two members of staff with a knife and demanded money.
He stole cash and then made off down Blackpool Road, possibly with another man, past Lane Ends Post Office. He was last seen on Kimberley Road.
The man who went into the shop was white, 5ft 10in tall, and spoke with a Liverpudlian accent.
The second man is described as wearing a light coloured hooded top and dark trousers.
Police are appealing for anyone with information or who saw the pair to contact them on 101 quoting log number 0425 of August 23.
The bookmakers was targeted in 2012, when a pair of masked raiders stole hundreds of pounds from the shop.
A member of staff had tried to fend off the attackers.