The 46-year-old singer was left "heartbroken" when her engagement to the Australian billionaire was suddenly called off and she is said to believe that the controversial church has something to do with it.
Insiders claim she feels James - who was a Scientologist between 2002 and 2006 - has been influenced by his business manager and former Church of Scientology spokesperson Tommy Davis, who has poisoned his mind against her.
A source told the NY Post newspaper: "Mariah and James were looking at homes in Beverly Hills to buy together in August, everything was fine, he was saying she was his soulmate, and he couldn't wait to marry her. Then suddenly he changed. In September, James suddenly seemed not like himself at all. Mariah is suspicious of Tommy, who has been managing James' finances, and she suspects he is controlling him."
