EL CAJON (CNS) - A man accused of attacking his father with a samurai sword over Christmas weekend must stand trial on assault with a deadly weapon and other charges, a judge ruled Tuesday.

John Cahan allegedly walked into his 69-year-old father's bedroom in Spring Valley around 3 a.m. on Dec. 26, roused the sleeping victim and angrily demanded that he hold out one of his hands so the younger man could cut it off.

Cahan, 39, allegedly swung the sword several times over his father, Allen Cahan, and brought it down, striking the victim in the lower leg.

The defendant left the bedroom but returned to try to stop the bleeding, according to authorities. About 90 minutes later, John Cahan called medics to the home, claiming his father had accidentally injured himself while sleepwalking, according to sheriff's Sgt. Mark Varnau.

A motive for the sword attack was not disclosed. Deputy District Attorney Chantal de Mauregne said the defendant's father is expected to recover from his injuries.

The defendant is charged with assault, elder abuse causing injury and first-degree burglary. He faces 12 years in state prison if convicted.

Judge Patricia Cookson ruled that enough evidence had been presented at the preliminary hearing for Cahan to stand trial March 28 at the El Cajon Courthouse. A readiness conference is set for March 7.