Leslie and Dr. Cahill are the only two murderers in the original episodes that hold a certain distinction. Halperin and Mason hold a similar, but slightly different, distinction.
Leslie Williams and Dr. Cahill are the only two murderers in the original episodes who commit the actual act of their murder while sitting down.
Halperin drowns his wife while he is on his knees (not technically sitting), and Eric Mason is actually lying down while on the phone orchestrating the provoking of the dogs.
I just thought of a murderer I may have overlooked...was Norman Paris standing when he dropped the mixer in the bathtub, or did he actually sit down before doing so? I can't remember.
I also didn't count murderers like Riley Greenleaf, who is sitting in his car when the bomb goes off killing Eddie, but he gave Eddie the drugged wine and rigged the bomb while standing. (If he had activated the bomb by remote control while sitting in his car, then it would have counted, but he is just enjoying a cigarette while waiting around to make sure that the bomb does go off.)
no E you did fine....paris was not sitting when he threw the mixer in the tub...and riley wouldn't have counted because as you say, the drugging of eddie and the rigging of the bomb was done while he was in the apartment.
I looked at this one carefully before posting my original question, and at the moment she fires the gun she is standing up next to the bed. (I think she is lying down on the bed during the fantasy sequence.) After firing the gun, she immediately runs to the body.