The Costcutter store on Hawton Road in Newark has been targeted by robbers twice within the span of five days.
The latest incident happened on 10 November when a man had lunged at the shopkeeper and forced his way into the till at around 4.10 pm.
The offender used a screwdriver to threaten and steal around £100 and cigarettes.
The shop was earlier hit by a robber on 5 November. The offender then asked for 80 cigarettes and some tobacco, but snatched the items and left without paying.
The Co-Op store on Lincoln Road in Newark has also been a victim of robbery in between on 8 September.
The offender is alleged to have leaned over the counter and taken cash from the till, pushing away a shop assistant who tried to stop the robbery.
Officers from the Nottinghamshire Police said the three incidents could be linked.
“Our investigation into these incidents is well underway, including reviewing CCTV and conducting door to door enquiries in the area,” commented Detective Sergeant Jamie Moore, who is investigating the incident.
“I would encourage anyone with information to come forward. People should also be vigilant if anyone approaches them trying to sell cigarettes. If this happens, please get in touch with us.”
Anyone with information is requested to call Nottinghamshire Police on 101, quoting incident number 498 of 10 November.