Update

During a stop on our geology field trip in the Marin Headlands area, we saw several park ranger vehicles drive by with the lights flashing. When we were ready to continue five minutes later, they'd blocked off the main road, and we were detoured to no man's land.
The reason for this, we just discovered, was that less than half a mile away from where we'd been, some guy had pulled over on the side of the road and was, apparently, yuking. Rangers noticed and tried to question him, but he was acting weird, so they searched his car. Lo and behold, there in the trunk was his ex-girlfriend, whom he'd very recently killed. That's when the rangers called in the cavalry. Presumably, the dude was planning on doing a body dump over the cliff. The excitement of our near-brush with a murderer was spoiled by his idiocy. A stealthier criminal would have picked a time other than midday on a sunny weekend to do his body-dumping.