he fourth season of the CBS police procedural series The Mentalist premiered on September 22, 2011 and concluded on May 17, 2012. The season picks up immediately after the events of the third season finale in which Patrick Jane was arrested for the public murder of the man he believes is the notorious serial killer Red John, who murdered his wife and daughter. Throughout the early part of the season, it is revealed that the man Jane killed wasn't Red John.

Overview from themoviedb.org