SEASON two of American documentary TV series Making a Murderer is set to premiere on October 19, bringing with it a new lawyer named Kathleen Zellner.

She is the new attorney for 56-year-old Steven Avery, who is accused of the murder of photographer Teresa Halbach. We take a closer look at the life and work of Kathleen Zellner.

4 Illinois-based Kathleen Zellner has been appointed as Steven Avery’s new attorney Credit: AP2011

Who is Kathleen Zellner?

Kathleen Zellner is a 61-year-old attorney practicing in Chicago’s Downer Grove suburb in the city of Illinois.

She specialises in wrongful convictions.

Zellner founded her law firm in 1991, and has since exonerated 19 men wrongfully convicted of their crimes.

Many of her clients are pro bono – meaning they are not charged legal fees due to no or low incomes.

Thanks to the convictions she has been able to have overturned, there have been a significant number of changes to laws in her home state of Illinois and across the US.

Zellner attended Concordia University in Montreal, Quebec, for her undergraduate degree and obtained her law degree from Northern Illinois University

She is the only trial attorney in the United States who has won five multi-million dollar record verdicts in the span of just 11 months.

Zellner also represented a victim of convicted serial child molester and former USA Gymnastics team doctor Larry Nassar.

4 Steven Avery pleaded not guilty to the murder of photographer Teresa Halbach in 2005 Credit: AP2006

How is she helping Steven Avery?

Zellner has been appointed as Steven Avery’s new attorney.

The 56-year-old was convicted and sentenced to life in prison in 2007 for the murder of photographer Teresa Halbach.

Making a Murderer focuses on Steven Avery and his nephew Brendan Dassey and their fight for freedom.

In the trailer for the second season of the documentary, Zellner says: "I have one goal and that's to overturn the conviction of Steven Avery."

She has also said that "the deeper we dig into the Avery conviction, the more evidence we uncover of his innocence.

“It does not matter how long it takes, what it costs or what obstacles we have to overcome — our efforts to win Mr Avery's freedom will never stop."

4 Brendan Dassey claims he and his uncle Steven Avery raped Teresa before stabbing and choking her to death Credit: AP:Associated Press

What has she done so far?

In July 2018, she filed a 599-page document with the Wisconsin Circuit Court in Manitowoc County.

Zellner also asked the court to allow her to supplement her filing with a CD containing 2,499 pages of data downloaded from Brendan Dassey's family laptop.

Zellner said the CD contains evidence that Bobby Dassey, Brendan's older brother, gave false testimony and is a legally viable alternate suspect in the murder of Teresa Halbach.

The document and CD include images of violent pornography in which women are being violated and tortured.

Zellner says she can prove that this pornography was largely accessed at times when only Bobby Dassey was home.

Bobby Dassey was a key witness for the prosecution in the original trial of his brother and uncle.

4 Teresa Halbach went missing after going to take photos for Auto Trader magazine

Who was Teresa Halbach?

At the time of her death, Teresa Halbach was just 25 years old.

The photographer from Wisconsin was born in 1980 and grew up on a dairy farm near the town of Green Bay.

She had two brothers and two sisters, and had travelled to Mexico, Spain and Australia.

She was described by friends as “energetic and spontaneous” and “very outgoing and brave”.

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When did Teresa die?

On October 31, 2005 Teresa went missing after going to photograph a car for Auto Trader magazine.

A search party was sent out by her ex-boyfriend Ryan Hilegas after he discovered she was missing.

On November 5th, the search party came across Teresa's dark-green Toyota Rav4 on the Averys' property.

Reports at the time of the discovery claimed “tree branches covered its front end, a sheet of plywood and a rusty car hood leaned against its side, the license plate had been stripped off".

Later, police found Teresa's license plates, a pair of handcuffs and leg irons in his house and dried blood in Avery’s bathroom before finding human remains which were later proved to be those of Teresa.

Brendan Dassey later confessed to aiding Stephen Avery with Teresa's murder.

He claimed that both he and his uncle raped Teresa before stabbing and choking her.

They then allegedly burning the body in a fire.