I shot someone with a stun gun and now he's dead. Could I still be considered a pacifist? [duplicate]

I was going for a pacifist playthrough, and so I used the tranquilizer rifle and stun gun almost exclusively.

During the Cloak & Daggers side-mission, I was aiming to incapacitate Double-T, with the first obstacle being the henchman sitting on the couch outside his apartment door. I took out my stun-gun and made short work of him, but as I was dragging him away from where he collapsed I noticed that he appeared to be dead:

This is the first time I've had someone die after shooting him with the stun gun. Just to try it out, I reloaded and shot him with the tranquilizer rifle, only to have him die again (maybe he has a severe allergy to being unconscious).

So, is this just some sort of weird glitch, or does this actually count as a kill, thus disqualifying me for the pacifist achievement?

Solution 1:

Yes, this qualifies as a kill, sadly. You can also get kills from the tranquilizer sniper rifle, and if you kill someone after you've knocked them out. People have said it happens more often when you headshot with it, but frequently backing up your saves and checking everyone is the best way to go.