Investigators say Melinda Duckett shot herself to death Friday, the day after she was grilled by Grace in a telephone interview, and hours before the interview aired.
Grace told ABC News on Friday that it was more likely guilt than the media that drove Duckett to kill herself. "To suggest that a 15- or 20-minute interview can cause someone to commit suicide is focusing on the wrong thing," she said.
Duckett's 2-year-old son, Trenton, disappeared late last month. Duckett had said she found his crib empty one night, along with a 10-inch cut in the window screen above it. Investigators have been looking into Duckett's movements just before the boy vanished.
In the CNN Headline News interview, Grace grilled Duckett, at one point demanding to know, "why aren't you telling us where you were that day?"
Duckett's grandfather accuses Grace of "bashing" her. He says the strain of her son's disappearance and the media attention "sent her over the edge."
A spokeswoman for Grace called the suicide a "sad development," but said the program would continue to cover the case.
Police using cadaver dogs failed to find the 2-year-old during a search Thursday in the Ocala National Forest.
They found a stuffed animal, but don't know whether it belonged to the boy who disappeared from his bed almost three weeks ago.
Police say they have no physical evidence linking her to the area of the forest searched by investigators Thursday.