Witnesses to a fire that gutted a wooden storage addition on the north side of the Kamloops Food Bank say they saw a man take off from the scene just before flames and smoke broke out Thursday night.

The fire broke out around 8 p.m. and set off the building's alarm system.

One woman who spoke to police said she was walking up Wilson Street when she saw a First Nations youth, between 18 and 23 years old, run away from the structure and take off on a girl's bike.

"It went up just like that," she said. "It just went whoosh."

She estimated he was about five feet eight inches and 140 lbs. with long black hair.

"The food bank is just to help people," she said, disconcerted that anyone would deliberately go after the social agency.

Another woman who lives nearby said she heard someone call out "arsonist" so she called 911.

Her boyfriend also saw the youth hanging around and making noise by the food bank.

She speculated it could have been someone angry that the food bank took down a canvas shade tent it had erected for clients waiting in the sun.

Neighbours complained about it because it was becoming a target hangout for prostitutes and drug dealers at night.

"It attracted not nice people," she said.

She called RCMP last week because someone had broken into the structure that burned up Thursday night.

Food bank employee Wes Graham directed firefighters to an office in the main building where they could get keys to a cube van the agency uses to pick up donations. It was backed up against the burning addition.

Graham said the structure was used as a garden shed and to store food.

He said the tent was removed because it was drawing a lot of noise and activity in the evenings.

The food bank needs non-perishables to replenish its stock. Donations can be made at the food bank until 3 p.m. Friday, then you can give at grocery stores.