Milo bit the cat again over the weekend

I got his human aggression under control, but getting him to lay off the cat is one heck of a challenge! So far we just locking the cat up in the basement so he can have free time in the house. Then we tie him back up (in the living room), so the cat can be free to roam the house.

Any advice on this cat issue. Hes gotten less aggressive with her, so now I can't even tell when hes going to strike