A backpack packing a number of explosive devices was found Monday in a storm channel under a bridge near Anaheim. Orange County bomb squad investigators detonated the hand grenades about 1:15 p.m. in a containment vessel, and the rest of the explosives were boomed about 2:45 p.m. in a larger open-air trailer, Orange County sheriff's spokesman Jim Amormino said.
The bag, found by a county work crew in a drainage ditch near Orangethorpe and Lakeview Avenues, contained six grenades, a number of blasting caps, canisters, fuse ignitors, black powder, white powder and other items.
Amormino told KPCC's Rob Strauss that the longer the bag sits, the more unstable it becomes.
"[The explosives are] all located in this backpack, which has been there for a while. We can tell by the deteriorating condition of the backpack. But because they have been there for a while, makes them even more volatile."
Amormino told KCAL 9 that other items were found "that I cannot talk about at this time." He told KPCC investigators have yet to apprehend a suspect.
“It was an intentional act, and we do believe that whoever placed those items there has some type of knowledge regarding explosives," Amormino said.
Law enforcement officials evacuated several nearby businesses, and Lakeview Avenue in Placentia was closed between La Palma and Orangethorpe Avenues. The FBI joined the investigation.
Detonating the items will be "an ongoing process," Amormino told KPCC, explaining that the powders were the most unstable, followed by the canisters and then the grenades. "They will be detonating at the site, only because they are volatile. And this will be done in separate increments."
This story has been updated.