Run away trouble teenager

my son (15) run away from home , claims he hates me. police strougle with him to bring him to me, refuses to came back home. I opted not to send him to a home group or cps and released him to my sisters home 4 days ago he hasn't slept there a single night I have no Idea were he stays and the police department say they can't do anymore. his still attend school although he sometimes late, skips classes, his grades are the lowest, disrespect teachers and anyone he feels like, his been in several fist fight out of school please help thank you. p.s. I'm  a single parent.