HOUSTON -

Arson investigators are trying to figure out what started a small fire inside a northwest Houston warehouse.

The fire broke out around 9:40 p.m. Wednesday at the Presto Warehouse on W. 6th Street and N. Shepherd Drive.

Investigators said the fire started in some boxes under a desk in the office area of the building.

Officials say the building's sprinkler system was able to keep the fire from spreading.

There is nothing electrical around the boxes, so arson crews are investigating.

Fire officials say no one had been inside the building since it closed around 5 p.m.

No one was injured.