Four Killed in Apparent Murder-Suicide : Violence: Woman, ex-husband, their son and her boyfriend are found shot to death in home. An investigation is continuing.

A woman, her ex-husband, their 12-year-old son and her boyfriend were found shot to death Wednesday in an apparent murder-suicide on a peaceful, tree-lined street in South Pasadena.

The bodies of Jane Larsen, 49; Gene Larsen, 64; Ben Larsen, 12, and Michael O’Brien, 44, were discovered in a tiny beige house in the 1000 block of Foothill Street shortly before 9 a.m.

Police were tight-lipped about the killings, but sheriff’s officers, who joined South Pasadena police in the investigation, acknowledged that Gene Larsen brought a 12-gauge shotgun to the house and that the recently finalized divorce may have been the cause.

“At this point,” said sheriff’s spokesman Fidel Gonzales, “we can’t tell who did the shooting, but the former husband came to the house. The divorce was final last week and it probably had something to do with this.”

A 12-gauge shotgun and a 9-millimeter semiautomatic handgun were found at the scene, authorities said.

Police said that at least three of the victims had been killed with the shotgun: Ben was shot in the head and arm, Gene Larsen was shot once in the chest and Michael O’Brien was shot in the head. No details were available regarding the weapon that killed Jane Larsen.

Gene Larsen was described by acquaintances as a man with a bad temper who could not accept the divorce.

Jane Larsen taught disabled children in the Los Angeles Unified School District. Gene Larsen was an insurance agent and Ben was a student at South Pasadena Junior High School. O’Brien taught children with learning disabilities for the South Pasadena School District.

A horrified neighbor discovered Ben’s body sitting upright in the living room of the house his mother had rented about a year ago after the breakup of her marriage. Police found the bodies of the adults in a bedroom.

Concerned school officials had phoned a neighbor when Ben failed to show up for class Wednesday morning. The neighbor peeked through a window of Ben’s home, saw the body of the youth and ran screaming to the home of Ricardo Delgado across the street.

Delgado entered the home and saw a boy sitting on the couch as though he was watching television. Overhead, a shiny red banner was strung across the room, reading: “Be My Valentine.” Everything looked in perfect order, he said.

Delgado described himself and other neighbors as “depressed as hell. We’re shocked and mad that it’s always going on and seems to get worse--the violence. And that we can’t prevent it and that it happened to really nice, sweet people that don’t deserve it.”

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Lucile Baker, who was a neighbor of the Larsens for about six years when they lived on nearby Collis Avenue, said Jane Larsen “was always afraid” of her husband. “He was always smarter than you or you or you. That’s why she had to leave.”

Baker said that Jane Larsen was unable to continue making the mortgage payments on the Collis Avenue house after the separation and rented the little home on Foothill Street. The property belongs to Caltrans because it is in the right of way of the long-proposed extension of the Long Beach Freeway through South Pasadena.

“Jane was a wonderful lady,” Baker said. “She had a wonderful son.”

Gene Larsen worked for the Prudential insurance company in Pasadena until he quit in September. A fellow employee, who declined to be identified, described him as “a little forceful. Everything was wrong with the company and that sort of thing.”

A former neighbor who asked not to be identified said that Gene Larsen was a good father who would take Ben on helicopter rides in connection with his membership in a military reserve unit. But he said Larsen “wasn’t a good person.”

He said that Jane Larsen told him a few years ago that her husband was carrying guns and recently said he could not accept the finality of their divorce.

Les Adelson, superintendent of South Pasadena Unified School District, praised both Jane Larsen’s son and Michael O’Brien.

“An outstanding, delightful young man with outstanding citizenship,” he said of Ben, who was an “A” student. Adelson said that a crisis intervention team is being sent to Ben’s school to help students deal with his death.

He said that O’Brien, who taught at Monterey Hills School, “was a great guy, a warm, friendly, caring person.”

Adelson said parents of O’Brien’s learning-impaired students were being urged to come to school with their children today to help them deal with their grief.

“These are fragile kids,” he said, “and we feel it will be a real support to have the parents there.”