General Motors Co. is asking a federal judge overseeing more than 100 ignition-switch lawsuits to halt discovery in a Georgia case in which one of its former senior attorneys faces deposition as soon as November.

In a letter to U.S. District Judge Jesse Furman, overseeing the multidistrict litigation (MDL) involving the ignition switch, GM has moved to halt planned depositions of up to 15 people, including William Kemp, its former top attorney on safety issues, in Cobb County, Ga., State Court.