The California Supreme Court Thursday unanimously upheld the death penalty of a man who killed a Concord restaurant owner and her disabled adult daughter during a robbery of their Orinda home in 1995.

Corey Williams, 36, was sentenced to death in Contra Costa County Superior Court in 2000 for the first-degree murders of restaurant owner Maria Corrieo, 74, and her daughter, Gina Roberts, 53.

Another of Corrieo's daughters discovered the two women dead of gunshot wounds to their heads and with their hands tied behind their backs on Aug. 16, 1995.

Williams, then 19, was one of three men who had planned to rob Corrieo. They had learned from a restaurant cook that the owner, who mistrusted banks, carried large amounts of cash and had an estimated $30,000 in the trunk of her car.

One of the other men, David Ross, testified against Williams at his trial and said Williams told him he shot the women because Ross called him by his nickname, "C-Dog," during the robbery, and Williams was afraid he could be recognized. The nickname was tattooed on his hand.

The men stole between $40,000 and $50,000 as well as a television set.

Ross was sentenced to 20 years in prison and the third defendant, Dalton Lolohea, was sentenced to life in prison.

The high court, in a ruling issued in San Francisco, rejected Williams' appeal claims of errors in jury selection and in evidence rulings.

The panel also turned down Williams' claim that he should not have been allowed to act as his own lawyer during the penalty phase of the trial.

Justice Carol Corrigan wrote for the court that Williams had a right to represent himself and that the trial judge, Superior Court Judge Richard Arnason, adequately "questioned him at length about his request for self-representation and his understanding of the consequences."

During the penalty proceedings, Williams expressed no remorse and told the jury, "My actions are my actions and mine alone. I chose the life I led."

Williams has the right to pursue further appeals in the federal court system.