Fake IRS 1-800-508-4126

I got the following phone message:

I'm calling you from the criminal investigation department of the IRS. The matter at the hand is extremely time sensitive and urgent, as it after audit we found that there was a fraud and misconduct on your tax filing, which you are hiding from the federal government. This needs to be rectified immediately, so do return the call on our toll free number. The number is 800 5084126, again 800 5084126. Thank you.

It called again from a different number, twice:

My name is officer Mycorinary[unintelligible] I'm calling from the criminal investigation division of IRS. The matter at the hand is extremely time sensitive and urgent, as after audit, we found that, there was a fraud and misconduct on your tax which you are hiding from the federal government. This needs to be rectified immediately, so do return the call as soon as you receive the message. The number is 2407601284, I repeat again 2407601284. Thank you.

The number is in Maryland near D.C. The voice sounds like a synthesizer, and it's likely that the officer's name was rendered as a mishmash of phonemes.