Police and fire crews were called to the Co-op supermarket in Market Deeping last night after a security alarm sounded and smoke was seen billowing into the sky.
Lincolnshire Police was notified an alarm had been activated at the premises, in Godsey Lane, at 9.20pm. Lincolnshire Fire and Rescue Service also sent an appliance to the scene.
Police officers carried out a thorough search but there was no sign of any break-in or other criminal activity.
Lincolnshire Police said this morning it is believed a security alarm inside a cash machine which faces out into the supermarket’s car park had malfunctioned after torrential downpours over the weekend.
A spokesman said: “It was initially thought someone was attempting to break into or steal the ATM, but it transpired that heavy rain had got inside the machine and it incorrectly thought it was being stolen.
“An alarm was triggered and a SmokeCloak anti-theft device was activated.”
SmokeCloak is an anti-theft device commonly used by cash handling, financial and banking companies. Once an alarm is activated, the area is cloaked with an impenetrable curtain of fog, reducing visibility to less than an arm’s length - making it much harder for thieves to steal money or goods.