Here's one way to find a cheating online chess player

If normal chess rating is 2300+ and chess960 rating is lower than 1500 or a chess online master that does'nt play chess960 is a cheater, right?

If you suspect someone is cheating, please use the Help & Support link at the bottom of each page. When that page opens, click on the left side option where it says Contact Us and submit a 'Suspected Cheat' ticket.

Also see this page

http://www.chess.com/forum/view/community/chesscom-policy-on-cheating

We provide tools to report cheating to our staff. But having several constant and redundant threads on the topic that circulate with the same questions and comments over and over again isn't helpful, and instead causes people to worry more than they need to. If you want to discuss cheating, please do it in this group

http://www.chess.com/groups/home/cheating-forum