Here's an automated transcription of the robocall:
Hi my name is David Gray. This message is intended to contact you regarding an enforcement action executed by the United States treasury and needing your serious attention. Ignoring this will be an intentional second attempt to avoid initial appearance before magistrate judge for a grand-jury for federal criminal offense. My number is 606-259-9417. I repeat it's 606-259-9417. I'd like you to call with us and help us to help you.
As the others noted, male, middle eastern accent, serious, almost threatening tone. This is the second of these types of scam calls I received. I actually got a live person on the last one, and he threatened me - said he was an "officer". I hung up and he called back, again threatening. I said to hold on, as I was going to conference in the police so we could get this straightened out - of course, he disconnected immediately.
"Matthew Colson" called me today with a very alarming dialogue, said a warrant has been issued for my arrest for tax evasion and tax fraud. He has a heavy Eastern Indian accent, could barely understand him. He said authorities are on their way to my house to place me under arrest. He said his Treasury Dept. ID # is 720689. I was given a phone # for "David Parker", same Indian accent, very threatening dialogue. I finally just hung up. The # I called them back on is 850.764.6834....I explained that 2011 is 5 years ago and I don't recall who prepared my taxes that year. What in the world is this?!?!?!?