Man Held in Deaths of Ex-Girlfriend, Mother : Killings: Amtrak police arrest him at Union Station. He had checked into motel where victim’s car was found.

A 23-year-old man described by authorities as a jealous former boyfriend was arrested Sunday in the bludgeoning deaths of a Walnut woman he once dated and her mother.

Richard Russell Moon of Walnut was arrested by Amtrak police officers shortly after midnight at Union Station in downtown Los Angeles, after they received a tip from Los Angeles County sheriff’s detectives that he was preparing to leave the area.

Moon was held without bail in the deaths of his former girlfriend, Melitta Greig, 22, and her mother, Rose Greig, 53, whose bodies were found Saturday in the trunk of the family car.

“When they broke up, Richard wouldn’t let go,” said Father Bill Leser, pastor of St. Martha’s Church in La Puente, where Melitta Greig attended parochial school and her mother worked as the parish secretary and bookkeeper. “He was having a very hard time saying goodby.”

Dave Pooley, manager at the Fullerton AMC theater where Melitta Greig worked for the last seven months, described her as “bright, outgoing, a pleasure to be around, a take-charge kind of girl.”

Moon was not initially a suspect in the killings, although detectives planned to question him, Sheriff’s Sgt. Rey Verdugo said at a Sunday morning press conference. He became a suspect Saturday evening, however, when sheriff’s deputies spotted Melitta Greig’s missing Volkswagen Cabriolet convertible in a motel parking lot in Rowland Heights.

The car’s distinctive license plates--ATTILEM, or Melitta backward--had been removed and stashed in the car, Verdugo said. Moon had registered at the motel that afternoon, but deputies did not find him there.

Moon, it turned out, was on his way north, Verdugo said. He had called a friend for a ride to the Fullerton Amtrak station, where he boarded a train for Los Angeles and then bought a combination train and bus ticket that would take him as far as Fresno. He told the friend he was headed for Seattle, Verdugo said.

Moon never boarded his 1:50 a.m. bus in Los Angeles. Watching television, the friend’s mother learned that authorities were looking for him. Realizing that her daughter had just driven him to Union Station, she called the Sheriff’s Department, which according to Amtrak police Officer Joe Gross, contacted station authorities.

Gross said he and fellow Amtrak Officer Miguel Pintos arrested Moon without incident and held him for sheriff’s detectives.

“There was a relationship severed quite a while back,” Verdugo said after detectives interviewed Moon Sunday afternoon. “But he seems to have held a fascination for her.”

Authorities said they believe the mother and daughter were killed in their garage between 1 and 3 p.m. Friday. Rose Greig was last seen about 12:15 p.m., when she received a phone call in the parish office and left work abruptly. Melitta Greig never showed up for her 4 p.m. shift as a supervisor at the theater.

Robert Greig, Rose’s husband and Melitta’s father, discovered the bodies in the trunk of his wife’s car when he came home from work about 1 a.m. Saturday.

A piece of wood and a hammer found in the garage are being examined as possible murder weapons, Verdugo said.

According to friends and co-workers, Moon, a student at Mt. San Antonio College, met Melitta Greig a few years ago when both worked at an AMC theater in Puente Hills. They dated on and off until about six months ago, when Melitta broke off the relationship, friends said.

Theater employees said Moon was raised in Modesto and came to Walnut after his parents’ divorce. They said he would clown and roughhouse with other employees and patrons. Once, he lost his job for putting a dead mouse in the cash register as a practical joke, said Alice Rogers, a former supervisor.

A week ago, Moon called Rogers and asked if he could come back to work at the theater, she said. His job as a sixth-grade camp counselor was about to end, he told her.

“I told him to come by Sunday and we’d fill out the paper work,” Rogers said. “Sometimes he would pull some stunt, but he was one of the best workers I have had.”

For a time, the Greigs served as a surrogate family for Moon. He lived at their hillside home for a few months while he was between apartments and he still stopped by Melitta’s grandparents’ home for lunch and to pick up mail, said Linda Montoya, the Greigs’ next-door neighbor.

Moon’s arraignment on murder charges is scheduled for Tuesday.

Times staff writer Sheryl Stolberg contributed to this story.