As reported earlier Activision and Infinity Ward appear to be locked in a battle that is becoming more and more convoluted. First there are reports of the head of Infinity Ward being fired for alleged insubordination. Next come reports that Infinity Ward are owed royalties by Activision.
According to website Binge Gamer they were told that Infinity Ward has not seen a single penny of the $1 billion in revenue generated by the second Modern Warfare game. This has been stated by a variety of anonymous sources.
Perhaps this could be the root cause of the problem with some speculating that the West and Zampella had been in secret talks with rival publishers while still under contract. The current agreement between Activision and Infinity Ward expires in October of this year.
As of yet there has still been no official response from either organisation.