The sound of an animal in distress is an awful sound.
The sound of an animal in distress for 12 plus hours when you're unable to find who trapped them or where? Well that's enough to put you over the edge.
So, laymen and professionals... if you're going to put out a trap, check it regularly. I did not need to ever say I've heard an animal crying in fear (and hopefully not pain) for half a day.
Update: I contacted an animal rescue place and they said any traps must be checked every 24 hours. Without solid proof that it wasn't, I can't report them, but you bet I'll be tracking things if anything like this happens again.