Well he called Monday but I haven't heard from them since!
You can run the number to see what turns up - or you can contact the police agency directly and ask about the phone call (providing the agency with the name of the detective) - or you can do nothing and see what comes of it all.
If you are in fact being contacted by a real detective about a case you are involved in (are you involved currently in a police matter?), you do not have to answer any questions asked of you, and it is better if you exercise your right to remain silent and direct all questions to your attorney (and you will want an attorney if you are currently involved in a serious police matter).
Because this sounds a bit like a scam, I suggest you treat it that way until you learn differently.