Respawn Entertainment co-founder Jason West has left the company, sources close to the studio have informed me. Co-founder Vince Zampella is now the acting head of the studio.

The duo are best known for having created the Call of Duty series under Activision.

I’m told West has not been involved in active development for Respawn’s game for a number of months now, but it has not impacted development.

The company did not respond to my request for comment.

West founded Respawn after leaving Infinity Ward, a studio he also co-founded, in a contentious and public exodus during 2010 that resulted in a lengthy lawsuit with publisher Activision. Dozens of employees left at the same time, and many of them went with West to Respawn.

Respawn has been developing a first-person-shooter for Electronic Arts. The game has not yet been unveiled, but it is reported to have a sci-fi slant, and is expected to be unveiled at E3 this year.