WSU alum who lived on a ground level apartment with a slider a few complexes over from BK's with my other female roommates. Don't remember ever locking the slider. I don't think we ever did.

Also had a U of I BF during my last year at WSU who also had a house in Moscow with slider. Can't say I ever knew if that got locked.

Always think about this now. And always thought the slider was his point of entry. Totally think he tested the slider during one of those 12 surveillance missions he conducted before the murders.

...but then my father in law also used to say a lock only keeps the honest man out. I think there was no stopping BK, and I so desperately want to think otherwise.