This is a Pakistan or India based IRS scam. Do not fall for it. The IRS does not initiate any legal action via phone.
Read http://www.treasury.gov/tigta/press/press_tigta-2014-03.htm
As general background information, here are a few things you can do:
1) Report it to TIGTA under http://www.treasury.gov/tigta/contact_report_scam.shtml especially if you have become a victim (lost money, gave personal information etc.). You can also file a complaint with the Federal Trade Commission at ftc.gov/complaint (include “IRS Telephone Scam" in your complaint). This way you can also help the government establish specific fraud patterns.
2) Help kill their phone lines. The scammers use Voice over IP lines (e.g. magicJack (Ymax corporation)) to make it seem as if they are calling from the US. This is always against these companys' terms of service and can lead to immediate termination of their contract and blocking of their IP addresses for future attempts to register. Do a reverse look up of their telephone number (e.g. www.whitepages.com) to identify the Voice over IP provider and report it to the company and/or law enforcement (local police and/or state attorney general)
3) If you are really annoyed: call or write to your representative in Congress. As these scams happen all over the country maybe this will trigger a reaction and provide US law enforcement agencies with the political backing and the resources they need to work in India and Pakistan together with local authorities (it can happen, read: http://www.ndtv.com/article/india/ex-call-cen ... mmission-320427). A US task force has already been set up in Jamaica to nab scammers there (see http://www.ice.gov/doclib/news/library/reports/cornerstone/cornerstone7-1.pdf). You can use the following template for your letter (more powerful!) or email:
Same thing happened to me today. First time this guy called, I was working, couldn't answer and he didn't leave a message. Two hours later called me back and this time left a message saying something similar: he was from the Crime & Investigation department of the IRS, he was Officer John Wright, and the reason of the call was because they had an arrest warrant and was sent or was going to be sent to my physical address. He asked me to call him back to have more info about it. Instead, I am here checking this number and I found this!
Very helpful!!