Yeah if I remember right, Ben bent some rules (i think they stole a video tape or gave false testimony) to help his partner get custody of his son. The partner was feeling guilty and was going to come clean. Ben didn't like that/didn't want to get in trouble. He had his girlfriends brother break into said partners house to steal evidence. Brother ends up killing the nanny. Ben then has to cover that up and lie to his partner about it. Partner finds out in the last episode and they fight each other. That's all I remember.

Cooper getting shot was the last season unfortunately.