The bitter split between Los Angeles money management giant TCW Group and former executive Jeffrey Gundlach turned nastier Thursday, as TCW sued Gundlach, alleging that he stole confidential information and used it to launch a rival firm.

Gundlach, ousted as investment chief of $110-billion-asset TCW on Dec. 4, schemed for months with top lieutenants to exit the firm with vast amounts of proprietary data, the lawsuit asserts.

TCW also sought to portray the 50-year-old Gundlach as unfit to remain a company officer. The firm said it found marijuana, pornographic DVDs and magazines and “sexual devices” in his TCW offices on the day he was terminated.

Gundlach’s new firm, DoubleLine Capital, quickly fired back, asserting that TCW’s suit had no merit and accusing the company of resorting to “gutter” tactics. DoubleLine said it planned to file a counterclaim against TCW.

About 40 of Gundlach’s 65 TCW investment team staffers have defected to DoubleLine, which set up shop Dec. 14.

• Read the Los Angeles Times story.

• Read Dealbreaker blog commentary and link to the lawsuit.