New S2 Player

New player here and have read through some of the material on the posts, so apologies if this has already been covered. Like many of you, am fan of X-Com, and read the manual for S2 which led me to believe that if you brought back a stunned/uncon. prisoner after you killed all the rest, that you could learn a good deal more from doing this (simialr to the stunned aliens in X-Com). On my first mission, I ran into a named officer and promptly tried to bop him over the head several times with my Scout's billy club with no luck. Had to kill him. My question is: Is there a way to stun the opposition without killing them? If so, should I just wait for this ability/weapon later in the game or is it available to the first few missions players? Thanks for the help