Can police take you out of custody of your parents if your a minor in US?

This girl lied about my friend having oral sex with her.Hes 15.Her parents came by, and she tried to lie and say it happened in the house? by his mom is always home 24/7. She has no proof it happened,or anything to back her story up. How ever my friend has proof that she is obsessed with him and posted stuff all over myspace saying they did things. that were lies, but she denies that it was her, and that her friend put that on her myspace (B.S). He got interviewed by the detective when they came by and showed them the posts she put up. She will get interviewed soon, and if her story matches his story(because she can now describe what the house looks like since shes seen it) can the police take him away until hes proven iniscint? if hes still a minor