"You knew there was tension. You knew there was a lot of jealousy," said Janet Kerrigan, talking about the relationship between figure skating star Nancy Kerrigan and her wayward brother Mark.
Janet was married to Nancy Kerrigan's brother for four years, and according to her, he was a tragedy waiting to happen.
"He was a loaded gun," she said.
"He was dangerous?" asked INSIDE EDITION's Megan Alexander.
"Very much so."
Nancy's father Daniel died after a violent struggle with his 45-year-old son, who has been charged with assault and battery and may face more serious charges. He pled not guilty.
"What type of man is Mark?" asked Alexander.
"He's a very angry, confused, sick man," Janet said.
She said Mark was bitter that his own dreams of pursuing a career as a professional ice hockey player were shelved so that Nancy could pursue her skating.
"Mark used to like to play hockey. He told me they couldn't afford his hockey because they were paying for Nancy's skating."
"Do you think he was jealous of Nancy?" asked Alexander.
"He would just say, 'Oh, it's always Nancy. Nancy, Nancy.' That's what he would say. When there was a family function there was always an edge."
She says Mark drank heavily and would become violent. In an eerie foreshadowing of the fatal struggle with his father, she says he once tried to strangle her.
"Reports say that Mark had his hands on his father's neck in a violent struggle. Is Mark capable of that?" asked Alexander.
"He did it to me," she said.
She says after trying to strangle her, Mark kept her prisoner in her own home. "I couldn't get out. So what I did was I jumped out the window of the bedroom."
The couple divorced and Mark Kerrigan served three years in prison for the assault. Janet says when she reached out to Nancy Kerrigan and her family they didn't want to have anything to do with her.
"Not once did they ever call me and say, 'Are you okay? Is there anything we can do?' " Janet told Megan Alexander.
But she also said her heart now goes out to her former sister-in-law over the loss of her beloved dad. "I would never in my wildest dreams have believed that he would have done that to his father," she said.
Mark Kerrigan was not allowed to attend his father Daniel's funeral, held today outside Boston, because of his pending criminal case.
Watch highlights from Janet Kerrigan's interview here.