Yesterday I got a phone call from a client indicating they had just been called by the IRS and they were threatening to send the sheriff to arrest him unless he made immediate payment. He asked to talk to their supervisor and supervisor told him the same thing.
I told him it was a scam and not to worry about it. He tried to discuss it with me and I told him there was nothing to discuss, that it is a scam.
On my Webinar today, the IRS confirmed that threatening phone calls pretending to be from the IRS are the biggest scam going. Their recommendation is to immediately hang up the phone and not engage in a conversation with them. If they call back hang up again. They will then probably move on to someone else.
Now having said that, if you have been talking with the IRS for an extended period of time about a specific issue then, yes, the IRS may tried to call you. But, they should not threatening in the phone call and they will not tell you they will be calling the sheriff.
Here is a link to the IRS page if you need to report a scam http://www.treasury.gov/tigta/contact_report_scam.shtml