Kathleen Zellner, 58, has forged a career by taking on wrongful convictions and is seeking to overturn the 53-year-old's life sentence without parole over the death of Teresa Halbach, 25, in 2005.
She told Newsweek the suspects all knew Halbach: "We have a couple. I'd say there's one, leading the pack by a lot. But I don't want to scare him off, I don't want him to run.
"We have to have new evidence that could not have been obtained before that would result in no juror believing that Steven Avery committed the crime."
Zellner has a tough case on her hands as Avery has already exhausted all of his appeals available to him so only new evidence will reopen the case.
Undeterred, the lawyer has been very vocal in her belief in his innocence.
Zellner has also raised a number of points about the validity of evidence used to convict Avery in the 2007 trial.
It is hoped that new evidence using advanced Luminol testing will spark a fresh appeal.
Zellner said previously: "There was a very poor investigation done of the victim's background, who she was involved with and circumstances of her life.
"It had all the hallmarks of a wrongful conviction case and then when I met him I realised in the time I spent with him in 15 or 20 hours, I absolutely don't believe he committed this murder.
"I don't believe he is capable of committing a murder. But that's not the key thing - it's the evidence that's just flawed."
Zellner's reputation comes from the successful exoneration of 17 men and has won almost $90m (£62.7m) from wrongful conviction and medical malpractice cases.
The directors of the show, Laura Ricciardi and Moira Demos, have confirmed they have spoken to Zellner and are hoping to begin filming a second series as Avery once again seeks to prove his innocence.
There is also a legal defence fund for anyone wishing to help Avery's case.