DETECTIVES investigating two incidents in Chorley have released CCTV images in an appeal for information.
Officers said a man entered Premier Newsagents in Pall Mall carrying a knife around 5.35am on April 14.
The thief approached a staff member, a 57-year-old man from Chorley, urging him to hand over cash from the till.
The victim refused, fighting off the attacker and forcing him to leave empty-handed.
Police said at around 11.20am on the same day, a man also entered Collingwood Convenience Store in Collingwood Road carrying a knife.
He threatened a staff member, a 50-year-old woman from Chorley, before removing a quantity of cash and coins from the till.
Detectives said they think the same man was responsible for both incidents.
The thief was wearing a black jacket over a grey hooded top with a snood covering his face. He also had black pants, black footwear and black gloves.
Det Con Phil Hampson said: “We are appealing for information following a robbery and an attempted robbery in Chorley.
“On both occasions a man has entered the store brandishing a knife before threatening a shopkeeper.
“Both staff members have been left shaken by their ordeals and we need to find the person responsible.
“We are urging anyone who recognises the offender to contact us immediately.”
Anyone with information should contact police on 101 quoting crime reference SC1702837 for the first offence and SC1702849 for the second incident.