A 44-year-old maintenance worker was held in Los Altos for investigation in connection with the fatal shooting of his estranged wife and stepson. The shooting occurred hours after the wife complained that Rajko Barbir was at her home in violation of a court order, police said. Investigators said Barbir was arrested a day after police found Kay Barbir, 48, and her son, Robert Vukovic, 24, mortally wounded in their home. Mrs. Barbir had called police Saturday, saying "I don't want anything done about it, but he's here and he's not supposed to be," Police Capt. Donald Thomson said. Later, a man in a neighboring house said he heard several loud explosions. Police found Vukovic shot in the arm and chest and Mrs. Barbir shot in the head and abdomen, coroner's examiners reported. Thomson called Barbir, who was arrested in Walnut Creek, the "logical suspect" in the killings. "It all just tends to flow naturally," he said. "There were no signs of a robbery or burglary."