San Diego

Authorities are investigating a weekend arson that caused more than $100,000 in damage to a Mission Valley office building. Fire officials said three fires were set Sunday night in the Kruse & Associates office at the five-story American Savings & Loan Center, 5005 Texas St.

A passer-by reported seeing the building’s fire sprinklers on and called the Fire Department at 8:15 p.m. When firefighters arrived, water was cascading from the second story. Most of the damage to the building and offices was water-related due to the sprinkler system, a Fire Department spokesman said.

The fire at Kruse & Associates--an electrical engineering company--began when several sets of blueprints were lit with matches or a lighter, fire officials said. There was no evidence that a flammable liquid was used.