Intrigue and speculation mounted over the weekend as Mercedes revealed Nico Rosberg’s retirement from the Singapore Grand Prix was due to a “foreign substance”. An investigation found the steering column to have a residue of material used in a pre-event servicing which eventually led to electrical failure of the wiring loom. Mercedes did not reveal what type of substance this “material” was. Rosberg had to start the Singapore GP in the pitlane because of gear selection issues and when the race got underway the issue never did, he was eventually forced to retire. Team mate, Lewis Hamilton, won the race and now leads the drivers championship by three points as a result. Mercedes clarified in a statement; “Forensic analysis has revealed that the steering column electronic circuits were contaminated with a foreign substance,” the team said. “This occurred during our normal pre-event servicing procedures at the factory and the substance found is used as part of our standard servicing procedure. “The contamination was not visible and did not manifest itself until Sunday as Nico went to the grid, although the steering column was used throughout the weekend and the car fired up as normal on Sunday morning. “Nico could not command the clutch nor change engine settings. The car was ultimately retired because it was unsafe to execute a pit stop without command of the clutch. Fresh parts will be used at the forthcoming races.” The team didn’t confirm or deny if Hamilton was involved in the servicing procedure but later tweeted; “To clarify, the contaminant was a substance used in normal pre-event servicing of the component. #NotAConspiracy :)” The Formula One circus next heads to the Japanese Grand Prix, this weekend, on October 5th