PLACENTIA (CBS) — A backpack containing multiple hand grenades and other explosive devices was detonated Monday afternoon after being discovered near a bridge in Orange County.

KNX 1070’s Mike Landa reports workers found the backpack just before 9 a.m. in a drainage ditch on Lakeview Avenue between Orangethorpe and La Palma avenues in Placentia.

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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 detonated about 2:45 p.m. in a larger open-air trailer, Orange County sheriff’s
spokesman Jim Amormino said.

The backpack containing the grenades, black powder, white powder, fuse igniters, blasting caps, grenade fuses and two canisters was found just before 9 a.m. on Lakeview between Orangethrope and La Palma avenues under a bridge, Amormino said.

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Later, he said, investigators found “numerous” additional blasting caps near the backpack, which was significantly deteriorated, indicating it may have been in the ditch for quite a while.

The FBI was called in to help investigate “because of the sheer number of devices,” according to Amormino, who said it appeared someone deliberately buried the explosives.

Lakeview was expected to remain closed between La Palma and Orangethorpe through the afternoon, Amormino said.

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