EL CAJON, Calif. (KGTV) - Authorities are trying to determine if a fire that started at an El Cajon warehouse Thursday night was started intentionally.

Heartland Fire & Rescue officials said they received a call about a structure fire at a warehouse on 920 El Cajon Blvd. around 9:15 p.m.

Crews put out the fire in 13 minutes, according to a division chief.

During the firefighting effort, a man suffering from burns on his body walked into a nearby Walmart and was eventually transported to the hospital.

Investigators are working to clarify how he may be linked to the fire.

Meanwhile, investigators said the fire is considered suspicious given chemicals found inside the structure.

Several business owners in the area said there has been odd activity in the neighborhood lately and that this is the second fire on the block in a week.

Arson investigators are looking into the incident.