Three men armed with a sledge hammer, a crow bar and a knife forced their way into the kitchen area of the Beefeater restaurant on the Premier Inn site in Little Colliers Field, Corby, and attempted to gain access to the safe.
The incident happened some time between 10.40pm and 11pm on Sunday, 9 October when the three offenders threatened staff and asked for the location of the safe, which they were unable to gain access to.
The three men fled empty handed in a silver Volvo which had a defective rear light and no front number plate.
The offenders are described as white with local accents. One was around 6ft with a dark beard and a stocky build. He wore a balaclava, Nike jogging bottoms and a black top. He was carrying the sledgehammer.
The second was about 5ft 10in with a medium build. He wore black clothing and was carrying what looked like a crow bar.
The third offender was about 6ft with a stocky build and also wore black clothing. He grabbed a knife from the kitchen to threaten staff, none of who were injured.
The suspects are believed to have made off in a silver Volvo S60 which was captured on CCTV – an image is attached.
Anyone with information can contact Northamptonshire police on 101 or, alternatively, call the independent charity Crimestoppers, anonymously, on 0800 555 111.