An unknown male person called at approximately 10:14 AM on Tuesday, 2015 January 06, who provided the name of "Officer Henry Scott" .
This unknown person claimed to be handling the legal affairs for the IRS and asked to speak to person X about an urgent "income tax matter."
The man spoke with what sounded like a foreign accent, perhaps from India.  
The man provided no further identification or details.
This smells like some sort of SCAM.

I got same call today from this number at 10:17 AM on Tuesday, 2014 January 06, also talking about legal affairs from US  treasury. He said his name is Peter. As I ever received a couple of calls last year which said from IRS, I guess it's another SCAM.

Same message this morning, 10:33 AM, January 6, 2015..Called himself "Peter" and calling from US Treasury for tax matters. Also gave a case number and left this phone number to call back.

called 5:46 PM 1/6/2015 Called himself "Peter" and calling from US Treasury for tax matters. I let him to stop calling me, he didn't stop talking even I said stop spamming.

Officer Henry Scott is more like Officer Klutzski. This threat needs to be ignored...IRS doesn't call you at all. If the person is threatening, threaten that person back. Force them to hang up the call.