To catch a cockroach

Somewhere on this boat is a three legged cockroach! He is the3rd one on board and the 2nd one that got away. Unless it is actually just a sighting of a lone cockroach.  Doug had one that scooted under the galley sink cabinet several months ago. They all look alike to me.  Doug has had a total of 3 sightings so far.  Each time he tells me tales of the battle.  Last night he held up a cockroach leg.  I did not consider this a victorious battle.  I have been ever so careful not to bring anything on board that might have a cockroach in it.  I think they fly in with the wind.  Today I emptied several cupboards and put out some bait and a sticky piece of paper hopping to trap the intruder.  Only time will tell.