This particular incident wasn't even prompted by a crime. Someone with a clean criminal record happened to buy guns with his tax refund after being put on administrative leave over a work dispute; someone brought this to the attention of the police, who felt it warranted a pre-emptive mental health evaluation. Well, if you can use "warranted" for cases where the police don't bother to get a warrant.
The man has been released, his guns have been returned, and he has not been charged with anything. I hope he sues.