General Motors announced that Michael Millikin, who has served as general counsel since 2009, intends to retire in early 2015. His departure comes three months after GM came under several investigations following a massive recall over defective ignition switches that can suddenly cause the steering, brakes, and airbag systems to lose power, and has been linked to 13 deaths.

According to a Congressional report, GM engineers knew about potential problems with the ignition switches since February 2005, but decided against fixing the problem because it would take too long and cost too much money. During a congressional hearing, however, Millikin claimed he didn't know about the problems with the ignition switches until this year.

“This is either gross negligence or gross incompetence on the part of [Millikin], the notion that he can say, ‘I didn’t know,'" Sen. Claire McCaskill (D-Mo.) said during the hearing. She further criticized General Motors CEO Mary Barra for her decision not to fire Millikin.

Millikin, who joined GM in 1977, will remain in his position until the transition of the new general counsel is complete. The company will immediately begin an external search for his replacement.