NEEDHAM — It had been a couple of days since Laura Shifrina’s family had heard from her. So on Wednesday night, her daughter stopped by her elderly mother’s apartment to check in.

“When she opened the door, she discovered her mother, and it was apparent she had been a victim of some kind of sharp trauma,’’ Michael Morrissey, the Norfolk district attorney, said in an interview Thursday.

Shifrina, 81, had lived in a quiet public housing development since 2001. The apparent slaying, the town’s first in a decade, left residents deeply shaken, despite assurances by authorities that her death was an isolated incident.

“To have it happen in your neighborhood, it’s kind of earth-shaking,’’ said Bradley Walker, a neighbor in the Linden Street complex.

She was found by her daughter around 11 p.m. She had likely been killed a couple of days earlier, Morrissey said. The state medical examiner’s office would determine how the woman died but said it was “obviously a very suspicious death,’’ he said.

“Enough of the alarm bells went off with the police to obviously dig in pretty deep to start to gather evidence and information,’’ he said.

Shifrina’s family has been fully cooperative with investigators, he said. The woman’s daughter and other relatives declined to speak with reporters Thursday.

Authorities would not say why they believed the apparent slaying was isolated, leaving residents unnerved.

“She’s been here a long time,’’ said Maureen Farrell, 64. “I’m dumbfounded.’’

Farrell said Shifrina was a pleasant neighbor who enjoyed gardening. She kept to herself but would often wave hello. Neighbors described the 72-unit cluster of studio apartments, operated by the Needham Housing Authority, as a close-knit community of senior citizens and people with disabilities.

Aleksandr Yufa, president of the Massachusetts Club for Russian Speaking Scientists, said Shifrina was a Jewish refugee who immigrated to the United States about 15 years ago with her daughter and her family.

Authorities did not identify the daughter.

“She was an excellent person,’’ Yufa said. “It’s horrible.’’

She worked for the Moscow Aviation Institute as a computer software engineer before coming to America, he said. She was an active member in the science club and edited a bulletin called “Intellect.’’

“She loved editing,’’ he said.

Yufa said he last saw her Sunday at a funeral in Malden for the club’s vice president. When she failed to attend a club meeting this week, he tried to call her but got no response. He searched for her relatives online and called Shifrina’s daughter, Anna, who made the gruesome discovery.

“I don’t know who could do that,’’ Yufa said.

Yufa said he will miss “her unique personality.’’

“She was so friendly, gorgeous, nice-looking woman, and a dear friend,’’ he said.

After Shifrina’s body was found, authorities issued a bulletin for her car, a red 2011 Ford Fiesta with Massachusetts plates that had apparently been taken from the complex. The car was found Thursday afternoon on Dorchester Avenue, according to police. Investigators declined to release further details.

Shifrina was very fond of the car, neighbors said. Jennifer Riley, 27, said she often saw her coming and going and recognized the beeping sound her car made when she locked it. Shifrina usually drove alone and would typically return with groceries, Riley said.

“She always had very pretty flowers,’’ Riley said. “I rarely saw her with any visitors.’’

Riley said she was shocked by Shifrina’s death.

“Everyone looks out for each other here,’’ she said. “It’s a very safe community . . . you never expect this to happen in your backyard.

The Needham Housing Authority held a meeting Thursday and had grief counselors on hand. Paul Dumouchel, executive director of the authority, said that “a number of residents are naturally upset.’’

“It’s going to be an ongoing process, and we’re going to be following the lead of the police,’’ he said. “It’s a very safe area and unfortunately it just shows you it can happen anywhere.’’

Ann Murphy, who has lived in the Needham complex for 11 years and attended Thursday’s meeting, said residents were on edge.

“People think nothing happens in the Needhams, the nice middle-class neighborhoods,’’ Murphy said. “I think you’re seeing some safety concerns with public housing. We’re a microcosm of some of the problems in the world — mental illness, the elderly — at times this place has its issues, but never to this extent before.’’

The last murder in Needham was in 2007 when William B. Dunn, 41, a Norwood irrigation contractor, beat Robert Moore, 78, to death inside his home after an argument. Moore’s murder had been the first since 1989.

John R. Ellement and Aimee Ortiz of the Globe staff contributed to this report. Jan Ransom can be reached at jan.ransom@globe.com. Follow her on Twitter at @Jan_Ransom.