I always find this hard to get my head around. If an allegation of a criminally serious nature is made such as rape, how is the law enforcement not running the show?

If detained by College authorities why not sue for false imprisonment? Or slander etc. It sounds like an inquisition. Or am I missing something here? Is this specifically a USA thing?

Also if an allegation is made anonymously, does the alleged victim get legal advice and suggestions to seek a rape kit? If its anon how does the College reply to the alleged victim regarding their investigations?