BOSTON -- Investigators are taking a closer look at the 96-year-old roommate of a Dartmouth nursing home resident who was strangled in her bed last month, a plastic shopping bag tied over her head with shoelaces.

Investigators have told the family of Elizabeth Barrow, who turned 100 in August, that criminal charges could be filed in connection with her death as soon as Friday.

Meanwhile, new light is being shed on the 100-year-old's relationship with her roommate.

Barrow's only son, Scott, 61, said his mom never got along with her 96-year-old roommate and their relationship became even more hostile in recent months.

He said the roommate allegedly complained about Barrow's many visitors and even made threats when the two debated which one should get the bed by the window, with the roommate saying she should have it because "I'm going to outlive you."

Family members asked the staff at Brandon Woods Nursing Home to make a change, but Barrow insisted she could patch things up.

Her son said police found his mother with a Cumberland Farms bag over her head.

"I'm not going to get into anything more than what the medical examiner said, which was asphixia by manual strangulation," Bristol County District Attorney Sam Sutter said.

Barrow's roommate was moved to a psychiatric facility shortly after the murder. Scott Barrow said he saw her in a nursing home hallway after the slaying and he said she looked at him and said, "You're going to blame me for this and you're wrong."

Police have not released the name of the roommate, and have not named her as a suspect.

The district attorney's office refused to comment except to say that the investigation is just beginning. A grand jury reportedly heard evidence in the case on Thursday and Scott Barrow said he was told criminal charges could be filed as early as Friday.