I answered "Maybe I'm capable but I've never given it serious thought" rather than "I don't believe I'd ever be capable of it except in extreme circumstances" because, you know, never say never. 
Honestly, though, I've never seriously considered murdering anyone. I can't think of a single person that I hate enough to want to end their life.
On the occasions that I've imagined killing someone it's always either been in the bounds of fiction (If I were in this character's situation, how would I have done it?), in self-defense scenarios (how bad would things have to get before I felt like killing the person was my only way out of the situation?), or in the proverbial "walk a mile in their shoes" situations (What would need to happen in my life to make me do what Jeffrey Dahmer/Susan Atkins/Ted Bundy/Ed Gein did?)
Honestly, though, I've never seriously considered murdering anyone. I can't think of a single person that I hate enough to want to end their life.
On the occasions that I've imagined killing someone it's always either been in the bounds of fiction (If I were in this character's situation, how would I have done it?), in self-defense scenarios (how bad would things have to get before I felt like killing the person was my only way out of the situation?), or in the proverbial "walk a mile in their shoes" situations (What would need to happen in my life to make me do what Jeffrey Dahmer/Susan Atkins/Ted Bundy/Ed Gein did?)
Teenaged X-Files obsession + Bermuda Triangle episode + Self-led school research project = Atheist.
