Tim London was a henchman of Shredder's. April O'Neil discovered him delivering chemicals to Dr. Koss at Mergenterprises, causing her to suspect Koss was up to something. While Koss was being controlled by the Grem, it is unrevealed what link London and Shredder had to their plot other than delivering the chemicals that were used in the mutagen developed by Koss under Grem control.The Fifth Turtle