When trying to trap the various varments that killed our chickens over the years, my husband would mostly bait the trap with the dead chicken (if you have a corpse). Canned cat food is a nice bait, since it's so stinky. But of course, you will need to keep your cats inside for a bit. Lol we...
Don't free range until you solve the problem. My sympathies for your losses. I would think either catch him or kill him...probably both. Do you have a dog?