Three new episodes of The Staircase, the acclaimed docuseries on Michael Peterson's case, will air on Netflix this summer

Kathleen Peterson, an esteemed member of the community in Durham, North Carolina, was found dead at the bottom of her mansion’s staircase in December 2001 — her body bloodied, her head battered — and before long, authorities had charged that her husband, novelist Michael Peterson, was the killer.

But was he?

The ensuing legal saga stretched until February 2017, when according to local media reports Michael, then 73, entered an Alford plea to voluntary manslaughter in his wife’s slaying. He was released from custody with credit for the seven-plus years he’d already spent behind bars.

“It has always been, and remains today, the State’s position that Michael Peterson is responsible for the death of Kathleen Peterson,” the district attorney reportedly said in a statement.

Still, Michael maintained he was innocent but had little other recourse. Prosecutors said they hoped the plea brought “a measure of justice” to the 48-year-old Kathleen’s family.

Throughout the final developments in the case, Michael was trailed by a documentary crew. This summer, their work will premiere on Netflix in three new installments of the true-crime docuseries The Staircase, which first aired over eight episodes in 2004. (Kathleen’s family has reportedly been critical of the filmmakers in the past.)

PEOPLE is exclusively revealing news of the new episodes; a trailer is above.

Writer-Wifes Death, Durham, USA - 24 Feb 2017
Michael Peterson (at microphone) in February 2017
| Credit: AP/REX/Shutterstock

The Case So Far

By the time of his plea hearing last year, Michael had already been convicted once of first-degree murder in Kathleen’s death, following a closely watched investigation and trial that made national headlines.

In a further twist, a judge vacated that verdict in 2011 and ordered a new trial.

All the time, theories swirled from those who felt authorities had not gotten at the truth of what happened in 2001. Perhaps most bizarrely, in recent years, some argued publicly that Kathleen had been fatally attacked by an owl.

Michael’s Alford plea, though technically a kind of guilty plea, did not officially resolve the underlying questions: In court, he acknowledged prosecutors had enough evidence to convict him but he did not admit guilt to their accusations.

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“Accepting this Alford plea has been the most difficult thing I’ve ever done — ever,” he said afterward, continuing, “The second most difficult thing I ever did in my life was to sit through that trial and I listened to lies and perjury, fake evidence, made-up evidence, withheld evidence. … So many times I wanted to jump up and scream, ‘Liar! This is not right!’ But you don’t do that in court.”

Prosecutors reportedly described it differently, with the district attorney saying, “It is clear that some evidence that was admitted during the 2003 trial may no longer be available or deemed admissible at a second trial. This decision was made after careful consideration and in consultation with the family of Kathleen Peterson.”

The Staircase‘s new episodes will be released on Netflix this summer, after airing at the Tribeca Film Festival later this month. An exact release date has not been set.

The network is also set to release Evil Genius: The True Story of America’s Most Diabolical Bank Heist, a four-part docuseries tracing a 2003 case in Pennsylvania. It will premiere on May 11.