Jason West and Vince Zampella, former heads of Call of Duty studio Infinity Ward, are suing Activision for US$36 million and control over the Modern Warfare franchise, according to a report by Bloomberg.

"Activision terminated their employment weeks before they were to be paid substantial royalty payments as part of their existing contracts for Modern Warfare 2," the pairs' lawyers at O'Melveny & Myers LLP wrote in a statement.

This follows on from the announcment that Activision was planning on expanding the Modern Warfare franchise with a new game by Sledgehammer Games .

As the legal battle between Activision and former Infinity Ward bosses, Vince Zampella and Jason West, intensifies, the world's largest publisher has supposedly requested internal documents that could prove the former studio heads were planning to defect to Electronic Arts.

According to G4TV, which cites an internal Activision memo obtained by a "source close to the company", the accusations of in "insubordination" may be due to an attempt by Zampella and West to establish a new studio with any one of the publisher's competitors.

The memo says that Activision is looking for internal documents that mention any past, current or future projects, including Modern Warfare 3. More importantly the publisher is looking for "documents regarding any potential 'spin out' of IW," and "documents regarding West and Zampella's communications with Activision's competitors, including but not limited to Electronic Arts."

The importance of these documents to Activision's case may be why the studio was left under the supervision of the publisher's security shortly after the dismissal of Zampella and West.

Activision has responded to the ex-Infinity Ward founders' lawsuit, saying they are "disappointed" and once again mentions unfulfilled "obligations" as justifying its actions.

Earlier this week Activision fired the founding figures of Infinity Ward among accusations of disobedience, to which the former execs, Vince Zampella and Jason West, responded with a lawsuit claiming US$36 million and control of the Modern Warfare franchise.

"Activision is disappointed that Mr. Zampella and Mr. West have chosen to file a lawsuit, and believes their claims are meritless," the company said in a statement.

"Over eight years, Activision shareholders provided these executives with the capital they needed to start Infinity Ward, as well as the financial support, resources and creative independence that helped them flourish and achieve enormous professional success and personal wealth.

"In return, Activision legitimately expected them to honor their obligations to Activision, just like any other executives who hold positions of trust in the company. While the company showed enormous patience, it firmly believes that its decision was justified based on their course of conduct and actions. Activision remains committed to the Call of Duty franchise, which it owns, and will continue to produce exciting and innovative games for its millions of fans."

Also to fire someone because they might move elsewhere. Also how come Activision has the power to sack someone from another company run by the people they are sacking? Or have I missed something?