LOS ANGELES >> A 60-year-old man fatally shot his dementia-stricken wife at their home and then walked into a convalescent home today and killed his sister, according to police, who described the shootings as apparent mercy killings.

Lance Holger Anderson of suburban Santa Clarita surrendered at the nursing home and was booked on suspicion of murder, shocking neighbors who described him as a chatty, friendly man who doted on his frail wife.

“He treated her like she was a jewel … because she was so fragile,” Gale Madrigal said.

Anderson walked into the Country Villa Sheraton nursing facility in the North Hills area of Los Angeles shortly before 9:30 a.m. and shot his sister Lisa Nave in the head, police said.

Nave, 58, had been at the home for about five years and was in a vegetative state or coma, police said.

David Chabolla, who lives in the room next door to where the shooting took place, said nobody recognized the noise of the gunshot.

“Everybody thought it was a balloon (popping) until they went in that room,” Chabolla said.

Police arrested Anderson as he sat in the courtyard.

The man “was just sitting down right in the patio,” Chabolla said. “I didn’t know it was him. I just saw him with his head down.”

It wasn’t immediately clear if Anderson had a lawyer who could comment on the case. Calls to home and cellphone numbers listed in public records went unanswered.

In a statement, nursing home officials said they were saddened by the shooting and “many thoughts and prayers are with the family.”

After learning of Nave’s death, family members called Los Angeles County sheriff’s deputies and asked them to check on the welfare of Anderson’s 63-year-old wife, Los Angeles police Lt. Paul Vernon said.

Deputies found the wife’s body at the couple’s three-bedroom town house on a curved, tree-lined street in the community of Canyon Country in northern Los Angeles County.

The wife, whose name wasn’t immediately released, died from a small-caliber gunshot wound, sheriff’s Lt. Holly Francisco said.

According to family, the wife was suffering from dementia, Vernon said. He characterized the shootings as “apparent mercy killings.”

However, a neighbor who spoke frequently with Anderson said he indicated the woman was having some sort of hormonal problems.

Neighbors reported hearing two loud booms Tuesday night that they mistook for firecrackers.

Nearby residents said the couple had moved in about six months ago.

Anderson seemed like the “sweetest guy you could ever imagine,” Madrigal said.

Kristen and Lee Booker said Anderson offered them food and help moving furniture after fire damaged their home in September. Another neighbor recalled Anderson fixing her flat tire.

Neighbors said Anderson indicated he had moved from Arizona because of his wife’s health. He often talked to neighbors but his wife was more secluded. Neighbors recall her exchanging a word or two as she sat on the couple’s patio, smoking or drinking coffee.

Sometimes Anderson was bending over her, caressing her hand, Madrigal said.

Two weeks ago, Anderson offered Madrigal his artificial Christmas tree.

He told Madrigal that the couple wouldn’t be doing anything for Christmas this year, she said.