A former Trust Company of the West employee intentionally snuck confidential data out of the company and misled investigators who tried to recover it, a former TCW senior vice president testified.

Jeffrey Mayberry, a subordinate to fellow former TCW executive Jeffrey Gundlach, took the stand on Monday in a high stakes trial between Gundlach and his former employer that could be worth hundreds of millions of dollars to the winner.

Mayberry, who is a co-defendant in the case, said he downloaded information -- including TCW's mortgage-backed securities proprietary database -- onto a flashdrive before putting it in his car in December 2009 on the same day he was put on administrative leave.

Under questioning by a TCW lawyer, Mayberry acknowledged that he then handed over another, different flashdrive to a company investigator, knowingly hiding the one with TCW information.

TCW fired Gundlach, known as the "king of bonds," in late 2009. In the following weeks, Gundlach set up his own asset management firm, DoubleLine Capital, and roughly 40 TCW employees who had worked under him migrated to the new firm.

TCW sued Gundlach shortly thereafter for theft of trade secrets and creating unfair competition in the market, among other allegations. Gundlach counter-sued, alleging that TCW owed him wages.

TCW is a unit of French bank Societe Generale (SOGN.PA).

In testimony on Monday in a Los Angeles courtroom, Mayberry maintained that the flash drive did not contain information proprietary to TCW. Instead, he said he wanted to keep a copy and determine who owned it after consulting with Gundlach and a team of lawyers.

Mayberry's testimony is scheduled to continue on Tuesday.

The case in Superior Court of California, County of Los Angeles is Trust Co of the West v. Jeffrey Gundlach et al, BC429385.