A bookmaker is offering a £10,000 reward after it was targeted by a knife-wielding robber twice in three days.
A man entered William Hill on Ribbleton Lane, Preston, on Saturday night, brandishing a knife and demanding money.
He fled the premises with around £300 from the till.
A similar incident occurred at the bookmakers on Monday January 13, when around £200 was taken.
Police are linking the offences and believe the same man could be responsible. They issued CCTV of a man they want to trace.
Det Sgt Martin Pearson from Preston CID said: “These are serious offences and I would appeal to anybody that has any information about either of these robberies to come forward and contact Lancashire Police on 101.
“Fortunately nobody was injured and owing to William Hill’s internal security systems the offenders were only able to access a relatively small amount of cash been taken during the day.”
The robber was wear black clothes with a scarf over his mouth.