Police are hunting a knife-wielding robber who targeted three St Helens convenience stores in just six weeks.
In the first incident a man entered the Londis store on Dunriding Lane at about 2pm on December 3 armed with a large hunting knife.
He threatened staff before escaping with cash from the till.
Detectives believe the same offender attempted to rob the same store shortly before 2pm on January 9.
In that incident a man walked into the same shop armed with a similar knife and demanded cash, but they refused to hand anything over and he ran off empty-handed.
A week later, on January 16, a man entered the Londis store on Bradlegh Road, Newton-le-Willows, shortly after 6pm.
Again, the offender was armed with a knife - but this time it was partially hidden in his jacket pocket.
He demanded cash, but was forced to leave empty-handed when the shop assistant refused.
DI Martin Earl, of St Helens CID, reckons the same offender was involved in each of the three crimes.
He said: “The offender is described as white, aged in his early 20s, around 5ft 10ins to 6ft tall and of a slim build. He spoke with a local accent. We believe that the same offender is responsible for all three incidents and we are determined to trace and arrest him.
“I would urge anyone who recognises the description or has any information about these incidents to get in touch with us as soon as possible.”
DI Earl added: “Convenience stores provide a vital service for local communities and we won’t tolerate offenders who threaten people and steal from those trying to make an honest living.
“We have been offering crime prevention measures to premises across Merseyside as part of an ongoing crackdown on retail crime and we have been ensuring that the two shops in question have been given this advice.”
Anyone with information can call police on 0151 777 6807 or Crimestoppers, in confidence, on 0800 555 111.