Had a case a little like this in high school. One of my friends parents got called to come to the school because he had been caught with drugs on campus. They get there and the cops harangue them for an hour before they let them see their kid. Only it turns out it was not their son. The school had two David Clarks and the wrong ones parents got called. David never new anything was wrong until he got home that night.
Hate to say it, but basically the police are immune from lawsuit unless it can be proven they acted with malice.
Ditto for a prosecutor.
They are even immune from civil suit if they lie on the witness stand under oath.
You may thank SCOTUS for that.