Only the IRS could tell you what they are checking and they probably won't. Sometime it is not even you that they are checking but someone who paid you and did not report the payment properly.
All you can do is wait or call the number for more information that should be on the notice along with the case number.
What type of letter? Is it a CPxxxx letter? (where xxxx is a number).
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
