Official: Fatal SoCal blast being probed as intentional Published on May 16, 2018 at 09:49AM by By MICHAEL BALSAMO, Associated Press LOS ANGELES (AP) — An explosion that rocked a Southern California medical office building on Tuesday, killing a woman and injuring three other people, is being investigated as intentional and investigators believe the blast may have come from a package, a U.S. official told The Associated Press. The explosion at the office building in Aliso Viejo — about 50 miles (80.5 kilometers) south of Los Angeles — blew siding off the walls, exposing insulation and framing. Authorities had not found an explosive device Tuesday night but were searching through debris that was left after the blast. The official said the information was based on a preliminary investigation.