LEXINGTON — Authorities are investigating a homicide here after a 49-year-old woman was found unresponsive in a vehicle on Worthen Road early Thursday morning.
Middlesex District Attorney Marian Ryan identified the victim as Shen Cai of Lexington during a news conference at the police station in Lexington.
As of 12 a.m. Saturday, no suspect was in custody.
Lexington police responded to Worthen Road around 12:30 a.m. Thursday following a call by the victim’s friends, who had located Cai in the driver’s seat of a white Honda CRV on the side of the road. She was pronounced dead at the scene, and investigators observed “suspicious trauma” to her body, authorities say.
The chief medical examiner’s office determined the manner of death, which was ruled a homicide.
Cai was found not far from Lexington High School, Ryan said at the news conference.
“Cai came to her death after sustaining multiple blunt trauma,” said Ryan.
Authorities believe the slaying was not a random act.
“We are confident at this time that the community is not at risk,” Lexington Police Chief Mark Corr told reporters.
Asked if Cai’s husband was a suspect, Ryan said Friday “We are very early in the investigation.”
According to Ryan, Cai had a daughter and her husband has a son. The Honda CRV was registered to the family, she said.
The homicide rocked the Baskin Road neighborhood, the leafy enclave where Cai lived.
Emery Wilson, a 63-year-old retiree, has lived in the neighborhood for nine years. He was helping a neighbor with their garden on Thursday when they were approached by police who asked if they knew anyone in the neighborhood who had video surveillance set up at their house.
He described the street as a type of place where people will stop for a chat while they’re out for a walk. “I’m completely shocked,” he said.
Other neighbors described Cai and her family as quiet. Some said the family kept to themselves. Others said they would have brief conversations with Cai when she was out in the neighborhood, but never anything beyond that.
Vidhi Thumma, a next-door neighbor of Cai, said she would exchange hellos with her while they were doing yardwork. Cai, she said, “seemed nice.”
Thumma said she was “shocked beyond belief” by the slaying.
“You don’t think it’ll happen in your neighborhood and to your neighbor,” she said.
Another neighbor, Jane Kramer, a 63-year-old who works in biotech, said she almost never saw the family outside, although she did see the husband smoking a cigarette outside his house Thursday evening. She believed Cai worked in the health care industry.
“It’s a little startling,” said Kramer of the violence. “It’s uncomfortable.”
Ken Kaitin, a 66-year-old professor who specializes in pharmaceutical regulation, said there would be long periods of time when Cai’s house would be dark “and nobody was around.” He described the family as private and recalled having a brief conversation with Cai about China, where she was from.
He called her homicide unnerving.
“I’ve lived in Lexington for 33 years and you don’t see this very often,” he said.
In a statement, Ryan’s office said investigators learned the victim was reportedly last seen by her husband and friends on Tuesday evening.
On Wednesday, the victim’s friends became worried after Cai had missed two scheduled appointments, and because she had previously reported to them that she had concerns about her safety, the statement said.
Authorities said after looking for Cai for several hours, the victim’s friends located her in the vehicle on Worthen Road and contacted police.
“This is an open and active investigation being conducted by the Middlesex district attorney’s office, the Lexington Police Department and the State Police Detective Unit assigned to the Middlesex district attorney’s office,” the statement said.
Danny McDonald can be reached at daniel.mcdonald @globe.com.