Mission Viejo Mother, Baby Slain : Crime: Businessman discovered the bodies of his girlfriend and son when he returned to the apartment after a trip. Neighbors knew little about the Taiwanese woman whose visa was about to expire.

A frantic call from a local businessman led sheriff’s deputies to an apartment where his 25-year-old girlfriend and their 5-month-old son were found murdered, homicide investigators said Thursday.

Tseng Jyi Peng, 50, who had been away on an overseas business trip, told authorities that he arrived at the apartment about 11:30 p.m. Wednesday and discovered her body sprawled across a living room couch, Lt. Randy Blair of the Orange County Sheriff’s Department said.

Deputies also found the body of the couple’s child in his crib in an adjoining bedroom in the second-floor residence in the Vista del Lago Apartments on Marguerite Parkway.

Blair said Peng is the chief executive officer of San Diego-based Ranger Communications. He was questioned throughout the night, and is not a suspect in the slayings, according to Blair.

No possible suspect, motive or exact cause of death have been revealed, although investigators said the woman may have been stabbed or bludgeoned.

But because there were no signs of forced entry to the two-bedroom apartment near Lake Mission Viejo, it appears that the killings were committed by someone the woman knew, Blair said.

“There is no evidence that leads us to believe this was done by an intruder,” Blair said. “We feel it was someone she knew.”

The woman, from Taiwan, was in this country on a visa that was about to expire, Blair said. She had been living in the apartment in the 608-unit complex since February and knew few neighbors, Blair said.

Authorities wouldn’t identify the victims, but according to county birth records, Peng had a child with a woman named Ranbing Ji on March 16, 1993, at Saddleback Memorial Medical Center in Laguna Hills. The boy was named Kevin Ji.

Also, a red Honda Civic that neighbors said had been driven by the woman living in the apartment is registered to a Jennifer Ji, according to the Department of Motor Vehicles.

A DMV spokeswoman said an Orange County coroner’s official had informed them that the slain woman is believed to be Jennifer Ji.

Residents of the apartment complex said the woman kept to herself and stayed in the apartment most of the time.

“I’ve seen her with the little baby, but there was very little contact,” said Diann Thaxton, whose bedroom shares a wall with the victims’ apartment. Thaxton said she heard no noises Wednesday night.

Authorities said little criminal activity has been reported in the history of the 6-year-old complex.

“This is the first time anything like this has happened here,” said three-year resident Lila Valy, who cried as police removed the bodies from the scene. “We’re shocked.”

Sheriff’s Sgt. Dave Remender said an autopsy would be performed today to determine the cause of death. The woman’s torso was on the couch and her legs were on the floor. It appeared that she may have been bludgeoned or stabbed, Remender said.

“We are ruling out any chance of gunshots. I don’t think there was any firearm involved,” Remender said.

The cause of the baby’s death remains uncertain, Remender said. He was found in his crib in a bedroom festooned with Mickey Mouse decor, but there was no obvious signs of trauma, Remender said.

No time of death had been determined.

“There was not decomposition (of the bodies) like you’d think,” Blair said.

Peng lives in Rancho Santa Margarita and had a “relationship” with the deceased woman, according to Remender. However, authorities said, when Peng called for help, he stated that he had found his wife dead.

A spokeswoman for Ranger Communications, which makes two-way radios and overseas communication devices, said a man named Jim Peng owns the company. Peng, reached at his home, declined to comment.

Times correspondent Geoff Boucher contributed to this report.