A Franconia man who stabbed his 66-year-old mother to death last fall was found not guilty by reason of insanity yesterday and was ordered by a Fairfax County judge to stay at the state mental hospital in Petersburg until he is cured.

Three psychiatrists who examined Ali B. Boushehri, 46, diagnosed him with schizophrenia, a mental disorder characterized by distorted perceptions of reality, disorganized speech and delusions. All three doctors concluded that Boushehri did not know right from wrong when he stabbed his mother, Batool Boushehri, nine times in the upper body as she lay in bed on the morning of Nov. 14.

Ali Boushehri was unemployed and lived in a town house in the 5200 block of Cannes Court with his mother and sister, Jaleh Boushehri. Assistant Commonwealth's Attorney Todd F. Sanders said Ali Boushehri called police about 12:30 a.m. to report he had killed his mother, then hung up the phone. Police found Boushehri outside smoking a cigarette. The officers then heard the screams of Boushehri's sister, who had discovered her mother and was trying to resuscitate her, Sanders said.

Karen Keeffer, a forensic psychiatrist who examined Boushehri, testified that he had been determined schizophrenic as early as 1990. She said he was hospitalized at Inova Fairfax Hospital in 1991 after mutilating himself, and he also believed he was receiving messages from outer space.

Boushehri felt he "has been possessed by an assassin," Keeffer said, and in describing the killing, "He felt controlled, like a robot, that this was something he was being forced to do against his will."

There had been no argument or disagreement with his mother before the violence occurred. Keeffer said Boushehri recalled his mother "woke up and told him to go back to bed, and that's when he began stabbing her."

Prosecutors did not oppose Boushehri's plea, and Circuit Court Judge F. Bruce Bach granted it, ordering Boushehri to Central State Hospital in Petersburg. In order for Boushehri to be released, he would have to petition the court and the judge would have to find that he no longer required hospitalization.

Family members watched and wept during the hearing yesterday.

"This has been a trying time for the family," Jaleh Boushehri said afterward. "My mother was very loved. We feel this was a good judgment for him. He needs help, and we hope he gets it."