Thieves stole money from a cash machine at Morrisons supermarket in Oakley Road, Corby.
The theft happened between 1.55am and 2.55am on Friday, September 27.
A police spokesman said: “It is believed that the offenders were four men, all wearing dark clothing. We believe that a woman may have witnessed the offence when she went to use the neighbouring cash machine and we are appealing for her to come forward.”
Police have not disclosed how much money was taken.
Witnesses to the theft, or anyone with information, are asked to call the police on 101, or Crimestoppers on 0800 555 111.