Police are searching for a car with Ada County license plates after Susie Ko was found slain in her Bay Area home.

A neighbor found the mother of four dead in her home late Friday after Kelvin Ko called about 10:20 p.m. and said his wife hadn’t picked him up at the Oakland airport after his flight from Boise Friday night, police say.

An autopsy conducted Monday determined the 55-year-old retired schoolteacher died from stab wounds and blunt force trauma to her head, according to police.

The couple’s son, Simon Ko, said his parents were renting a home in Boise and spent at least half their time here, but his mother had stayed in Hercules this month.

Kelvin Ko, 60, is “holding it together, but he’s very distraught,” said Detective Connie Van Putten, spokeswoman for the Hercules Police Department.

The couple’s 2011 Subaru Legacy was missing from the driveway, and police have released photos, including one of license plate 1A 1F680, in hopes someone will recognize the car and help crack the case.

There have been no confirmed sightings, but “that doesn’t mean we don’t want people to call,” Van Putten said. “We’d rather check out 100 or 500 bad leads than miss one that might break the case for us.”

Police noticed no signs of forced entry at the home or other stolen property. They’re planning to walk through the home with Kelvin Ko soon.

“He might notice something not so obvious,” Van Putten said. Van Putten said the crime scene remained closed Tuesday. The FBI helped collect evidence.

It’s the first murder in the 23,000-person town, which is about 20 miles northeast of San Francisco, since 2010 and the sixth since 2004.

“This type of violent crime is very rare for us,” Van Putten said.

The Kos’ four children, including a daughter who lives in London, attended a vigil Monday night in Hercules to honor their mother. Another vigil was planned for Tuesday night.

“There’s been an outpouring from all over the county to this family,” Van Putten said.

Meghann M. Cuniff: 377-6418