This is an IRS scam.  I got a call at 7:20 a.m. this morning from 415-230-2678.  The caller identified himself as "Mark Williams" from the IRS Litigation Department, but he had previously called me under another number (415-251-6327).  The IRS recently issued a warning about pervasive telephone scams here:

http://www.irs.gov/uac/Newsroom/IRS-Warns-of-Pervasive-Telephone-Scam

I gave "Mark Williams" a string of expletives, and hung up.  This is a scam.

I also got a call from this number threatening me with arrest and IRS fines and the ugent need for me to get an attorney. This is a fraud that was threatening, stating they tried to deliver arrest info and no one was at home to sign so now they'll take me in.  All a fraud.

complete fraud

please don"t have thesze people call me

We are reporting these people to the IRS  and authority.