A robber forced newsagent staff to lock themselves in the toilet after he emptied the shop’s safe.
The man, who is believed to have been armed, walked into the McColl’s newsagents in Grangeway, Rushden, just before 10pm on Sunday, January 25.
He demanded to know where the safe was and told the two staff members to empty it and put the money in a bag.
He then told the shop workers to lock themselves in the toilet while he escaped.
It is believed he may have fled in a silver people carrier which was parked behind the shops.
He was white and was wearing a jacket that was either pink, red or brown. He also wore blue jeans and gloves.
Witnesses should call Northamptonshire Police on 101 or Crimestoppers anonymously on 0800 555111.