The best place to farm for this trophy is on Pretty Boy's chapter on the bike mission right after the fight in the graveyard. Make sure that you have a shotgun equipped and after 1 or 2 hits on a cop, the circle button icon should appear for you to perform the bike rage attack. You should be able to pull this off at least 3 times in this stage. Each time just get your bike rage attack kills, finish the area, go back to Dead End, choose the graveyard mission, and do it all over again until you get the 10 kills for the trophy.