"Making a Murderer" subject Steven Avery's ex-fiancée Jodi Stachowski spoke out against him Wednesday night in an interview on "Nancy Grace." In the interview, Stachowski told producer Natisha Lance that she believes Avery is guilty of murdering Teresa Halbach and that his claims of innocence featured throughout the Netflix documentary series are false.

"It's been 10 years. Why are you talking to me?" the producer asked Stachowski. "What do you want people to know?"

"The truth," Stachowski said. "What a monster he is, that he's not innocent."

Stachowski defended Avery throughout the series, but she said during the interview that he forced her to lie to the producers of the show or else she would "pay for it." She also claimed that Avery was regularly physically and emotionally abusive to her over the course of their two-year relationship.

"He'd beat me all the time, punch me, throw me against the wall," Stachowski said. "I tried to leave, he smashed the windshield out of my car, so I couldn't leave him."

She also told the producer during her interview that Avery once told her "all bitches owe him because of the one that sent him to prison the first time and that he could do whatever he wanted."

Stachowski and Avery were engaged when he was arrested for the murder of the 25-year-old photographer Halbach and broke up with him shortly before his conviction in 2007. While Stachowski said that she had not seen "Making a Murderer," she added that she thought it was full of lies. She also said that directors of the documentary series asked her for a follow-up interview, but she declined.

"He's like Dr. Jekyll and Mr. Hyde. Semi-nice person and then behind closed doors, he's a monster," she said.

Watch the full interview below: