HERCULES -- The family of Susie Ko, with shock and grief visible in their eyes, said Sunday they haven't slept much since the 55-year-old was mysteriously found dead in her home on Friday.

The homicide, a rarity for this suburb, remained under investigation Sunday afternoon with neither a motive nor a suspect but with one key piece of evidence still missing: the family's 2011 sky blue Subaru Outback.

Authorities say the car and a set of keys vanished the night Ko was found with an injury to her head and what appeared to be blood on the floor next to her body.

Ko's adult children have spent the first 36 hours since their mother's death spreading information about the car and the case to thousands of people miles away from the family's tidy cul-de-sac home.

The Ko children have created a website and Facebook event page with pictures of the Subaru Outback and its Idaho license plate -- 1A1F680 -- which by Sunday had been read by more than 5,500 users and sent to more than 120,000.

Tips began pouring in from the greater Bay Area, Oregon and Southern California, according to the site.

"We want people to pay attention and know that we need them," said Diana Ko, 27, who along with her brother, Simon, 29, and sister Sophia, 24, flew in from Los Angeles over the weekend. Sandy Ko, 32, who works for Google in London, was on her way home Sunday.

From a relative's house just blocks from their home, the family on Sunday remembered Susie Ko as a creative spirit quick to crack a joke and always juggling projects, especially in the home's front yard. Ko taught for nearly a decade at St. Patrick School in Rodeo where her children also attended.

"She was one of the kindest people I've known," wrote Kristin Mitra, who identified herself as a former student, on the Facebook event page. "I was shocked. I'm still trying to wrap my head around all this."

Ko and her husband, Kelvin Ko, 60, moved to Idaho for his new job after the children were grown. They kept the house in Hercules and she commuted between the two, returning here to keep the yard tidy, her children said.

Police believe she was killed between 7 p.m. -- the last time neighbors saw Ko alive -- and 10 p.m. Her husband called neighbors to check on his wife after she did not pick him up from the Oakland International Airport at 11 p.m.

Simon Ko believes his mother may have been a target of robbery by someone who realized the house is often vacant or that she was home alone.¿ He asked for anyone involved in her death to turn themselves in to police.

"I know if my mom ever felt threatened she'd defend the house. Hopefully, they'll make a mistake and pay for what they've done," he said.

The family said the FBI is expected to arrive Monday. Anyone with information can call the Hercules Police Department at 510-724-1111.

To visit the family's website go to welovesusieko.com. To join the family's Facebook event page, go to on.fb.me/QWZEU1. There will be a vigil for Susie Ko at 8:30 p.m. Monday, Oct. 8, on Ash Court, Hercules.

Contact David DeBolt at 925-943-8048. Follow him at Twitter.com/daviddebolt.