I don't think they are going to catch Izumi unless he admits it to them ... Or Kei does.
Anyways ignoring all of that for a second, that was some of the most retarded series of events I have seen in awhile ... He tries to kill a girl, gets stopped so tries to kill the guy. When this fails he walks away as if nothing happened, and when they chase him he goes "Stop following me" "what do you want from me?" ... As if they are somehow creeps for not also pretending nothing happened ... That actually just seemed extremely stupid to me.