Warwickshire Police are appealing for witnesses or information following a robbery of a cash van at the Lidl in Bilton Road.
The incident took place at about 3.50pm on Tuesday afternoon (April 9).
Three or four men in dark clothes are reported to have approached a security van before threatening the driver with weapons.
The offenders are reported to have left the car park in a black Audi A3 estate car with a quantity of cash.
Dete Sgt Mark Greaves from Rugby CID said: "A thorough investigation has been launched following incident and we are working hard to locate those responsible for this violent robbery.
"As a result, the public may see an increased police presence in the area whilst enquiries continue.
"While I appreciate this may be have been an upsetting and scary situation which many people will have witnessed, we do believe it to be an isolated incident.
"I would ask that anyone who was in the area at the time of the incident and who may have dash cam footage or mobile phone footage to please come forward as soon as possible.
"Any information, no matter how small, could be significant to our investigation.
"If you witnessed the robbery or have any information please call Warwickshire Police on 101, quoting incident reference 256 of Tuesday April 9 2019."
Information can also be passed on anonymously through the independent charity Crimestoppers on 0800 555 111 or via their website www.crimestoppers-uk.org