866-978-6540

Does anyone know if this number is legitimate? Someone with a very thick accent claiming to be from the IRS called. I thought they had to notify by mail first not some 800-number.

There is a fairly common IRS or "tax scam" being practiced by scammers in both Canada and the USA.
USA tax payers should read this:
http://www.irs.gov/uac/Tax-Scams-Consumer-Alerts
Note particularly the links at that site, warning of the scam!

It's a scam. Do not give out your whole or part of your social security number

This person with heavy accent called and said IRS is charging criminal case against me. He said if I don't take this seriously it will effect my entire life. He said I can do two thing; one hire a lawyer or I can pay what I own to the IRS. He then goes on with the expense to hire lawyer and court fee.  He also said, police will arrest me when I go home and all my bank account will be freeze.  
So I said, IRS usually send letter to notify not calling on the phone and I need to go to IRS and find out. Then he said, He is calling from Washington DC and I have two hour to get there to resolve this problem. I said this is sound like scam, then he said I am doing my job and hang up. Please be careful anyone out there when you received this kind of call. First I was panic mode them my brain start working. The person name is Mike Brown. This may not be his name after all.

This is a scam.  The caller said that a warrant for your arrest is being serve at your place of residence for tax fraud and the Sheriff will be there at your place of residence to arrest you. Before any arrest warrants is issued there is a long process to get to this point and IRS does not employ the Sheriff for this type of work; IRS uses their own. Do not sent any information or give credit card number to pay whatever they are saying you owe the IRS.   And any case IRS send letters notifying you of a problem on you tax returns.  IRS does not call taxpayer by phone unless you have initiated the call first to them. This scam is targeting immigrants mostly that do not know the laws. So if you get such call:  Ask the caller for his badge Id, a return phone number and if you detect any hesitation or runaround that you will be informing the real IRS.    In all cases call your accountant or contact the IRS on their web site will have all the information.    

Just got a call from 866-978-6540 from a guy with a very thick accent claiming to be from the "IRS". He actually addressed me by "pierre*****n" all blended together( what i use for my typical username). Then he proceed to tell me that he has an affidavit to have me arrested and was asking me for my criminal attorney's information before he has the police come by and have me arrested. You can also hear a lot of people talking in the back ground like a call center. The call also went in and out and the caller was constantly saying "hello? what happened?". I would not give him any of my information so he said, "Ok, i will turn the affidavit in and have you arrested". So, if I go missing, please bail me out.....

Hmmm.. I too just got a call.  He asked me what number that they originally called me on.  I could hear people talking in background as well, as if it was a callcenter.  SEEMS LIKE A SCAM TO ME!  Very strange.   He said he would call me back that he had ot get my file.  seriously??  I told him go ahead, and leave me a nother msg because I don't have time for this.  It was odd. He sounded like he was from Nigeria.  How do they get the last for of my social??  Very weird.  I don't trust it at all.  I already filed my taxes back in Feb.  I have a terrible credit score as well, and I'm actually glad!  Short sale on a house.  So I don't think this is real.  I was in panick mode too. So weird!