This person calls as William Smith claims from IRS and has warrant for your arrest. If you hang up on him they know how to lock your phone and call as if they are calling from the police. They are IRS scammers and are very aggressive over the phone. They have middle eastern accents.

Don't give the crooks the time of day and let the phone ring without letting them leave you messages. IRS doesn't issue threats or forewarn of arrests, much less call you at random. Tell him to blow it out his backside if you talk to him. They can't do squat if you don't answer.

What a [***]  he called me and threatened me as well and said he was from the IRS as well. I'm making a police report on him. ..

This officer called me and left a message stating he was calling from IRS regarding bank accts and I had three hours to call him back if not I'd be arrested! He left his number but No area code, dummy! Good thing I did not pick up!

http://www.irs.gov/uac/Tax-Scams-Consumer-Alerts
http://www.treasury.gov/tigta/contact_report.shtml
http://800notes.com/forum/ta-8c2f64bf2b91fa5/irs-warns-of-telephone-scam

Report the Calls to the real IRS here:
•report the incident to the Treasury Inspector General for Tax Administration at 800-366-4484.
•You can also file a complaint with the Federal Trade Commission at FTC.gov. Add "IRS Telephone Scam" to the comments in your complaint.

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Do consider getting a call blocking device or phone.. You can google them and many are around $40.00 or so.If its a cell phone, some already have call blocking, if not, there are free apps on the web that will work for some. You can google this. If you have a smart phone, there is a free app called call control. Iphones appear to have apps also. Another one is called Mr. Number.