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:
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.