A North Texas woman has pleaded guilty to murder and been sentenced to 40 years in prison after she testified that she helped her husband gun down a district attorney, his wife and a top assistant in a revenge plot.

Kim Williams appeared in court Tuesday, two weeks after her husband, Eric Williams, was sentenced to death for one of the three killings.

She testified during Eric Williams' sentencing hearing that she was a "willing participant," driving the getaway car after the January 2013 shooting of prosecutor Mark Hasse and helping hide weapons after the March 2013 shootings of Kaufman County District Attorney Mike McLelland and his wife, Cynthia.

Eric Williams was prosecuted in 2012 for stealing county-owned equipment. He lost his job and law license as a result.