Hey all - I've lurked, but never posted in this thread. I'm familiar with the Tahoe area, and this thread has struck a cord with me. I just wanted to offer some perspective from experience on the weather/clothing scenario.
Her clothes are completely wrong - a lace bathing suit, sleeveless T-shirt. and canvas tennis shoes with no socks? Its freezing, theres at least 7 inches of snow on the ground and it was the middle of the night - what reasons could there be that someone would willingly get out of the car and walk to where she ended up being killed?
Just the fact that she was so underclothed makes me doubtful that she would willingly walk to the spot where she was killed - no only would her clothes have not been warm at all but they would have become soaking wet as well.
While I agree it was a little chilly, it wasn't really "freezing." Okay - technically it might have been below freezing, but I bet the air temperature didn't feel near that cold. I did a little research on the temps of the day. Using dry/wet adiabatic lapse rates you can estimate temperatures at an elevation if you have observations from a nearby site. The closest weather obs station in 1982 was Truckee, CA, which is at 5900 feet. Using lapse rate equations, I estimated:
For July 16:
At the lake (~6200 feet): low 50-51 degrees, high 71-72 degrees
At the meadow (~8700 feet): low 37-44 degrees, high 58-65 degrees
For July 17:
At the lake (~6200 feet): low 42-43 degrees, high 78-79 degrees
At the meadow (~8700 feet): low 29-36 degrees, high 65-72 degrees
I checked the nearest SNOTEL (snow monitoring) site as well, and no new snow of any great depth had fallen since about May. The newest snowfall was a tenth of an inch on July 8. It was old snow. Old snow is crunchy. It won't really get you wet.
I bring this up because I've lived in the mountains all my life. In July, on 7 inches of old snow, on a clear night, when it's 40-ish degrees? That's mild, if you're used to it. I'd be comfortable in Teva sandals, jeans, and a long-sleeve tee. And though 72 degrees might be chilly for swimming at Lake Tahoe, it was nice and sunny on the 16th - I'd be out enjoying the day no problem in what our UID had on.
I lean towards the theory that she'd spent the day at the lake, was coming back, they stopped there to get out and stretch/go to the bathroom/fool around/do drugs or drink, and something went really, really wrong. I don't necessarily think it has to be premeditated because the killer had a gun on him/her. Maybe they were afraid of bears. :waitasec:
Sources:
Weather Underground History for Truckee-Tahoe, CA
Marlette Lake SNOTEL Site