Chicago police say DNA on a cigarette butt found after the murder of a federal judge's mother and husband matches that of the Chicago electrician who killed himself this week.
The suspect, Bart Ross, shot himself to death Wednesday night when police stopped his van outside Milwaukee, Wisconsin (north of Chicago) because of a broken light on the vehicle.
Police found a note in the van confessing to the murder of Judge Joan Lefkow's mother and husband in her Chicago home in the U.S state of Illinois.
A Chicago television station said it received a letter from Ross saying the judge had thrown out his lawsuit against doctors he blames for disfiguring his face during cancer treatment.
Police had been investigating a white supremacist group that had also lost a case in Judge Lefkow's court.