Guilty by Association then.
Not sure really. I know there are certain circumstances where I
have to tell the police such as ongoing abuse or intention to commit suicide.
A apart from that the law is pretty clear: breaking confidentiality can mean a very large fine fine, considerable jail time (over six months I think), loss of professional qualifications, and my professional association can throw the book at me, and I'll be fired, and I think my employer can sue me too.
I think outside of those criteria above I'm legally obliged
not to tell the police.
Certainly we could keep the local police busy on drug hauls for weeks with a ten minute phone call...
That said, I've been guilty by association of
something most days since I started infants school.