Seems to be suspicious, Off Road Warehouse in San Diego has a big fire twice in a couple of months - update April 5th, and it's arson. 3.5 million dollars damage

The blaze erupted at the Off Road Warehouse near the intersection of Convoy Street and Balboa Avenue at about 1:30 a.m. The fire was still burning and sending a cloud of dark smoke into the sky nearly three hours later.

A Metro-Arson Strike Team (MAST) was called to the scene but would likely not be able to investigate what caused the fire until crews could gain access.

The blaze was the second at the same auto shop within a few months.

https://www.nbcsandiego.com/news/local/Massive-Fire-Burns-for-Hours-at-Auto-Repair-Shop-in-Kearny-Mesa-507772131.html
https://www.nbcsandiego.com/news/local/Multimillion-Dollar-Fire-Off-Road-Warehouse-Balboa-Avenue-Kearny-Mesa-is-Arson-508180521.html