But autopsy results showed the cause of death was strangulation, Sutter said. The district attorney's office declined to release other details.
A law enforcement official familiar with the investigation told The Associated Press that Barrow was found with a plastic bag over her head in a room she shared with a woman in her late 90s. There were no obvious signs of a struggle. The official spoke on the condition of anonymity because the person was not authorized to comment on an ongoing investigation.
Investigators were unaware of any conflicts Barrow may have had with others, the official said.
Barrow's only child, Scott Barrow, told The Standard-Times of New Bedford the family celebrated her 100th birthday on Aug. 21.
The family, including her three grandchildren, took her out for lunch and went shopping for winter clothes the day before she died and she was in good health and spirits, he said.
Barrow said his mother was born in New Bedford and grew up in the area. In the 1920s, she was crowned "Miss Rayon" and traveled around the region promoting a local textile company, New Bedford Rayon.
She worked for Bishop Stang High School and the Dartmouth public schools for several years as a cafeteria worker, he said.
Elizabeth Barrow and her husband, A. Raymond, both moved to Brandon Woods about 4½ years ago, he said.
"She loved the nursing home. She had a lot of friends there," he said. Her husband died about two years ago after 65 years of marriage.
Scott Picone, executive director of Brandon Woods, said Wednesday night that "the facility grieves for Elizabeth's family." He said Brandon Woods officials are cooperating with authorities.
The nursing home president, identified in public records as Frank Romano Jr. of Rowley, did not immediately return a call seeking comment.
Associated Press writer Ray Henry contributed to this report from Providence, R.I.