I haven't seen that many intentional intra-party kills. Here's my story, which I consider being killed by a party member, even though she didn't perform the killing blow.
So way back in 3.X, I was in a party that contained no healers except for the Druid. I was playing a wizard, and an exceptionally curious one at that -- she had a tendency to poke around and investigate anything weird-seeming, especially if a magical aura was involved.
Unfortunately, the other party members had a tendency to respond to any action she did that they didn't approve of with an "I attack her before she does anything!" In this particular case, the Druid critted me with a scimitar.
GM: "Uh, was that subdual damage?"
Druid: "Oh, sure, why not."
So being that I was critted subdually, I was 2 HP away from being unconscious. Ordinarily this wouldn't have been a problem, except that the Druid refused to heal me. So I tried to play it very safe -- we snuck through a hallway full of traps without setting any of them off, and when we went into an encounter with a bunch of undead and a couple of imps, I stayed way in the back and let the ranger and druid have at it while I cast terrain-deformation spells and walls.
Until of course a monster used a fear ability, and I failed my Will save.
So: I run away as far as I can, down the hallway, filled of course with traps. So I run into the first trap and take something like 8 HP of damage, and get knocked unconscious with near-full HP. Okay, no problem, I'll just wait for the party to save me, right?
Well, it turns out that while the party was busy with the rest of the undead, the imps followed me down the hallway and found a freshly unconscious wizard to jab to death.
Good times.