The streaming service Netflix has released the second part of its 'Making a Murderer' documentary.

It introduced the world to Steven Avery and his nephew Brendan Dassey - two Wisconsin men convicted of the brutal murder of photographer Teresa Halbach.

Filmmakers Laura Ricciardi and Moira Demos followed the case for over a decade, documenting the possibility of a massive miscarriage of justice.

At the end of the first 10 episodes of 'Making a Murderer', Steven and Brendan had been sentenced to life in prison - but remained hopeful about the possibility of their eventual release.

Left to right: Allan Avery, Dolores Avery and Steven Avery | Image: Netflix

The new chapter complicates the situation in unexpected ways, and introduces new characters.

Steven's story has attracted the attention of Kathleen Zellner - a hard-charging Chicago-based lawyer who specialises in overturning wrongful convictions.

She is taking up Steven's case and assembles a host of world-class experts who use the latest scientific methods to raise serious questions about the forensic evidence used to convict him.

Kathleen Zellner | Image: Netflix

Meanwhile, Brendan's post-conviction lawyers - Laura Nirider and Steve Drizin - are seeking to overturn his conviction in the federal courts.

They are arguing that Brendan's confession, the key element of the prosecution's case against him, was coerced.

Left to right: Scott Tadych, Brendan Dassey and Barb Tadych | Image: Netflix

This sets a series of legal challenges in motion with the potential to take his case all the way to the US Supreme Court.

Netflix says questions are raised regarding the validity of the State convictions; the pressure on the State of Wisconsin builds, while Teresa Halbach's family and supporters stand by the integrity of the verdicts.