This email with the subject "Must read, complaint" was received in one of Scamdex's honeypot email accounts on Thu, 19 Feb 2015 06:29:34 -0800 and has been classified as a Generic Scam.
The sender was "IRS Complaint" <firstname.lastname@example.org>, although it may have been spoofed.
This is a multi-part message in MIME format.
I filed a complaint on you and your accountant to the IRS(Internal Revenue Service). I sent copy of it in attachment.