From The New York Times 27 February 2016:
--------------------------------------------------------------------
Someone from the I.R.S. had just phoned, she said, to say a warrant for her arrest had been issued for failure to pay back taxes. ...“I told her, ‘Listen, this is a scam. Don’t do anything they are telling you to do,’” Mr. Smalley said...

...Since October 2013, about 900,000 people have reported getting a call from an I.R.S. phone swindler, and not all of these people hung up unscathed, the Treasury Department reported in January. Officials estimated that 5,000 victims had parted with a total of more than $26 million.
--------------------------------------------------------------------

article