A Lindsayfield supermarket was evacuated on Friday after a fire was started deliberately.
Police say the incident is being treated as wilful fireraising and are appealing for information.
The fire was started in the baby changing room in Morrisons.
Inspector Maurice Lindsay told the News the culprit set fire to paper hand towels within their plastic holder and then left the store.
The alarm was raised when thick, black smoke was discovered in the room and the store was quickly evacuated of staff and customers.
It remained closed for an hour and a half whilst debris was cleared and the fire service made sure the premises were safe.
Two appliances from East Kilbride and an appliance from Castlemilk supported at the scene.
Two firefighters wearing breathing apparatus extinguished the fire using dry powder.
A spokesperson for Morrisons said no one was injured and customers were calm and cooperative.
Store deputy general manager Stewart McLachlan told the News: “We are disappointed that this has been done to a well-used facility.
“Police are now investigating the incident and we are helping them with their enquiries.”
Inspector Maurice Lindsay of the Community Policing team has slammed the individual responsible for the “mindless act”.
He said: “This could have been extremely serious for members of the public and employees in the store.
“There is also the issue of damage to a local facility and damage to the business.
“It resulted in a loss of trade whilst the store was evacuated, which could result in the loss of several thousands of pounds.
“But, mainly, it showed a complete disregard for public safety.”
Any member of the public with information is being urged to contact Sergeant Dale Clinton at East Kilbride police office on 01355 564000