Same experience as others -- heavily accented male voice claiming to be Dennis Gray, I need to call 650-278-4439 regarding an enforcement activity by the US Treasury Department if I want to avoid an appearance before a magistrate judge and jury about a federal offense.  Note:  did not mention my name or my phone number, so this is a very generic recording.

This is obviously some sort of scam.

I just got the same call; heavily accented male voice claiming to be "Kenneth Gray" threatening enforcement action (by magistrate judge or grand jury) regarding a federal offense.  This is obviously a bogus call (I get these on an unfortunately regular basis) and no one should even bother to return the call.  Also, you can report this type of thing to the feds (although I have done so several times with no result).

Same as above.....
scam...

Same call. Obviously unsophisticated phising for stupid people to respond.
Didn't identify who call was supposed to be for.
Sounds like a good candidate for Guantanamo.

Male, calling himself Dennis Gray, with foreign accent left a voice mail message claiming to be making a second call as a representative of a Federal Magistrate in a criminal tax offense case and urged an immediate return call so he could help me out of an implied difficult situation. Of course I did not return his call.