During an unusual news conference in a Marietta law office Monday, attorneys watching from the back of the room remarked that they’d never seen this happen before: Plaintiffs trying to give back settlement money.

Kenneth and Mary Melton, who settled a product liability lawsuit against General Motors last year, announced they have asked a judge to rescind the deal and sanction the company for concealing evidence of the ignition switch defect they say caused their daughter Brooke’s death in a Chevrolet Cobalt.