Ray Bulgarin, who believed the diamonds were originally his, thought that the cook and Gay Tony conspired to rob Ray of the diamonds. Bulgarin decapitated the cook, leaving his head in a box on a rooftop for Luis Lopez to find when he walked into an ambush, which Lopez escaped.
In the PC version of Grand Theft Auto IV, the Cook has a full beard. However, he is clean shaven in the PS3 and Xbox 360 versions. In all versions of The Lost and Damned and The Ballad of Gay Tony he is clean shaven.
In a funny twist, the box that contains The Cook's severed head is actually the same one used earlier by him to smuggle the cake full of diamonds off of the Platypus.