Scott Barrow said his mother's roommate, who is in her late 90s, had complained to nursing home officials about the number of visitors his mother received and had made "threatening" and "harassing" remarks to her.
"She said, 'I'm going to have that bed next to the window,' and my mother said, 'Why do you think that?' and she said, 'Because I'm going to outlive you,"' Scott Barrow said.
Barrow said he asked officials at the Brandon Woods nursing home to separate his mother and her roommate, but they assured him the two were getting along.
The home's chief of operations, Scott Picone, said the roommates were offered room changes twice this summer, and both declined. Picone said the two women were friendly toward one another and often told each other "goodnight" and "I love you."
Scott Barrow said his mother, who had lived with the woman for about a year, tried to be "peacemaker" and told him she did not want to leave her room because that's where she and her husband lived for several years before he died in 2007.
The day his mother died, Scott Barrow saw her roommate being wheeled away from the room.
"She said to me, 'You're going to blame me for this ... but you're wrong,"' he recalled.
The district attorney has declined to comment on the roommate, and Scott Barrow said investigators haven't told him that the woman is a suspect. Authorities have said nursing home workers and residents are being questioned.