General Motors Co’s (GM.N) top lawyer will retire early next year, months after his department was heavily criticized for how it handled the automaker’s defective ignition switch that has been linked to at least 27 deaths. Michael Millikin, 66, informed GM of his decision, and the company will immediately begin an external search for his replacement, the No. 1 U.S. GM has faced criticism this year for waiting 11 years to recall millions of cars with ignition-switch problems that were linked to fatalities. GM declined to make Millikin available to comment, and he could not be reached.