The son of Oscar-winning actress Mercedes McCambridge shot and killed his wife and two young daughters and then took his own life, Little Rock, Ark., police said. A rubber mask of an old man's face was found near the body of John Markle, a 45-year-old investment banker, and was worn during some of the shooting, said Sgt. Eddie Alexander. Markle's wife, Chris, 45, was found dead in her bed on the third floor of the house, and his two daughters, Amy, 12, and Suzanne, about 8, were found dead on the second floor, police said. All three were dressed in nightgowns. A spokesman for Stephens Inc., an investment banking firm where Markle worked as an economist, said Markle had been on medical leave for about three weeks. McCambridge, 69, is best known for her supporting role in the 1950 film "All the King's Men," which won her the Best Supporting Actress Oscar. She was also nominated for an Oscar in 1956 for her supporting role in "Giant."