Caller ID said San Pedro, CA. Scam, sounded like middle eastern accent when I called the number. I told them they were obviously a scam, and if they called again, I would have them arrested for impersonating a Federal Officer. I'll not ever again answer a number I don't know!
"David Gray" left an automated message today. I'm aware of the scam so I decided to call back. When I asked him why he chooses to attempt to scam people out of their hard earned money rather than get a real job, he threatened that I will be arrested in 45 minutes and hung up.
Yet another unwanted phonecall, this particular instance from 424 287 5302, on Sept 2, 2015 time (twice today). Scam is about a difficulty with the US Treasury, wants you to call that number. Didn't. Annoying though.