Two investigators from the State Fire Marshal's Arson and Bomb Investigative Unit will lead the investigation into what went wrong with the Fourth of July fireworks display  that injured at least 40 spectators in Simi Valley.

According to reports,  at one point in the annual fireworks show at Rancho Santa Susana Community Park, a firework  exploded prematurely in its mortar and  knocked over other fireworks which then shot into the crowd of about 10,000 people. The injured suffered burns and "projectile wounds."

"Something went seriously wrong at that event and the arson and bomb investigators in the State Fire Marshal's Office will conduct a thorough investigation," said Alan Barcelona, president of the California Statewide Law Enforcement Association (CSLEA).  CSLEA's membership  includes 7,000 law enforcement, public safety and consumer protection professionals who work for the state of California, including arson and bomb investigators in the State Fire Marshal's Office.  "Finding out what went wrong and why will protect spectators at future events."

The investigators will work with the Ventura County Fire Department reviewing the park site, the evidence, videotape and interviews.