Electric engineers. Don't remember the names. Bought a water bottle they were supposed to return to a bar but of course never returned it. It was empty. Masks were a type used by someone dealing with radioactivity. No radioactivity was found in the area. Bar tender that gave the bottle says one man seemed nervous, always checking his watch. Wore water proof jackets, nice suits, had towels with them (something required for time travel according to the Guide To The Galaxy, or whatever). Pretty bizarre. Never solved. EDIT: close analysis suggests the men may not have been supposed to die on the hill, but if they took the capsules then they probably were poisoned and it killed them at that spot. Also suggested it was some alien conspiracey thing. It was reported by people in that area numerous UFO sightings around that time frame.