Placentia, CA (KTLA/CNN) - California authorities are investigating a backpack full of explosives that was found under a bridge.
The bag was spotted Monday morning in a county drainage ditch in Placentia.
That's nearly 40 minutes outside of Los Angeles.
A bomb squad detonated six hand grenades found in the bag.
The backpack also contained explosive powder, fuse igniters, blasting caps, grenade fuses and two canisters.
It's not known how the backpack ended up in the ditch.