Updated

A California man was charged with murder Friday after authorities said he shot and killed his dementia-stricken wife at their home and his sister in a convalescent home.

Lance Anderson, 60, faces two counts of murder, with special circumstance allegations of multiple murders and intentional discharge of a firearm with great bodily injury. If convicted, he could face the death penalty.

Anderson was being held without bail and his scheduled arraignment later in the day was put off until Jan. 13, said Shiara Davila-Morales, a spokeswoman with the Los Angeles County district attorney's office. It wasn't immediately known if he had retained a lawyer and no public defender had yet been assigned.

Coroner's Lt. Larry Dietz identified Anderson's wife as Bertha Maxine Anderson, 68. She died of a gunshot wound to the head after the shooting earlier this week in the couple's suburban Santa Clarita home.

Authorities said Lance Anderson took a taxi Wednesday from the home to the Country Villa Sheraton nursing facility in the North Hills area, where his 58-year-old sister, Lisa Nave, was shot in the head while she was in bed.

Anderson then put the small-caliber revolver on a nightstand and stepped into a courtyard, where he surrendered after police arrived, Los Angeles police Lt. Paul Vernon said.

Police initially said Nave was in a vegetative state or coma at the nursing home for the past five years, but Vernon said she was actually responsive and had been improving since a heart attack five years earlier left her in a yearlong coma.

After learning of Nave's death, family members called Los Angeles County deputies and asked them to check on the welfare of Anderson's wife.

Deputies found Bertha Anderson's body at the couple's three-bedroom town house on a curved, tree-lined street in Canyon Country. Sheriff's Lt. Holly Francisco said no weapon was found.

Family members told authorities that Bertha Anderson was suffering from dementia, said Vernon, who characterized the shootings as apparent mercy killings.

"He unilaterally decided to kill two people for whatever seemed like a rational reason to him," Vernon said. "But it isn't right for those who want those people to live. He can't make that decision."

Neighbors described Lance Anderson as a chatty, friendly man who doted on his frail wife. He had indicated that he had moved from Arizona five or six months earlier because of his wife's health.

"He treated her like she was a jewel ... because she was so fragile," neighbor Gale Madrigal said.

Sometimes Lance Anderson was seen on their porch caressing his wife's hand, Madrigal said.

Two weeks ago, Anderson offered Madrigal his artificial Christmas tree, telling her the couple wouldn't be doing anything for Christmas this year.