A four-day joint investigation by local and federal fire officials has determined that arson was the cause of Saturday's fire at Orson H. Gygi, 3500 S. 300 West.

A $5,000 reward for information that might lead to an arrest is being offered, Salt Lake County Fire Capt. Bill Brass said.Agents from the bureau of Alcohol, Tobacco and Firearms, the National Response Team and investigators from the Salt Lake County and Salt Lake City fire departments conducted the investigation.

Firefighters responded to the four-alarm fire at the wholesale restaurant supply warehouse at 2 a.m. Saturday.

Early damage estimate is $2.5 million.

Anyone with information should call the Interagency Arson Task Force at 524-5853 or the ATF at 888-ATF-FIRE.