Saw the new kitty hanging around right outside the door, hungry. Great time to set the trap. I use a Havahart Live Trap, set with canned, stinky food. These traps have a trigger pressure plate so when the kitty (or raccoon or fox or skunk) go inside, they get all the way in before stepping on the trigger plate, and the door behind them snaps shut but is far enough away to (hopefully) not catch any tail or fur in the closure. The trap has a spring loaded lock so it stays shut once the critter is inside.