Live traps are great. You can also bait the cat with some food. If you feed it for a bit, you might be able to pet it, if you can pet it, you can apply a flea preventative. Fleas are pretty bad this time of year in seasonal locations. Here, this year seems to be a bit worse. Remember, you have disrupted the lifecycle, but there may be ovum waiting to hatch. That said, keep vigilant for a good 90 days to fully rectify the problem.