One of our cats does this, but luckily the other one usually steps in and disposes of the prey, though it sometimes, erm, reappears later, if you know what I mean
A previous mog of ours managed to catch a bat once, brought it in alive first thing in the morning, and then dropped it on the floor. Unsurprisingly, the bat started flying around and ended up on the landing, where the ceiling is quite high, and it took me half an hour of swearing and cursing to bring it to ground in a towel that I kept flinging in its general direction. Mrs hay-char absolutely refused to appear and help me, and shut herself in the bedroom. When I caught the bat, I took it downstairs and released it outside the front door, whereupon it immediately turned round and came back into the house again. Aaaaaaaaaaaaaaarrrrrrrrrrrrrgh!
I was late for work that day but on the upside, my boss had never heard the excuse "I was trying to catch a bat in the house, and release it back into the wild" before and he didn't dock my pay.