16-Year-Old Boy Fatally Shot in Head in His Home : Violence: Police seek an 18-year-old who rented a room there. They view the death as possible homicide, but 2 witnesses say it was accidental.

A 16-year-old boy was fatally shot in the head Monday in his home, and police said they were seeking a friend who rented a room from his family.

The body of Armando Cuevas was found on the floor in a locked bedroom in the 1100 block of West Alton Avenue, Lt. Robert Helton said. No weapon was found.

“We’re treating this as a possible homicide,” Helton said. “Whether it was accidental is a possibility, but we’re not looking at it that way.”

The victim’s 7-year-old cousin and a teen-age friend called police from a public telephone in nearby South Coast Plaza at 1:50 p.m. to report the shooting. They told police an 18-year-old who rents a room in the three-bedroom house had accidentally shot Armando, Helton said. They said they had witnessed the shooting and then had fled to the mall to phone, he said.

Police were looking for the 18-year-old for questioning Monday night.

When officers arrived at the house, no one was there, Helton said. The front bedroom door was locked and police kicked it open. The body was lying next to a bed.

Police said Armando lived with two aunts, an uncle and the cousin, in addition to the boarder.

Armando’s aunt, Araceli Magana, said the 16-year-old had been living with her for the past 10 years. His mother died when he was 1, she said.

“He was a nice boy,” Magana said, crying.

He had met the 18-year-old at Saddleback High School, which they both attended, said Silvia Magana, the other aunt. The family allowed the older teen-ager to move in with them about a month ago because he had no family.

She added that Armando loved mechanics classes at school and liked to look at car engines with her husband.

Silvia Magana said the family had lived in the neighborhood, known as South Coast Metro, for more than two years.

Longtime residents in the quiet tract said they had never had trouble with Armando and his family.

Dick Bennett, 48, who has lived in the neighborhood for 20 years, said Armando and his family were “real quiet neighbors. I never had problems with them.”