One of the great open wounds of the 1970s black liberation struggle came closer to being healed on Saturday with the release of Delbert Orr Africa, a member of the Move 9 group who has been imprisoned for 42 years for a crime he says he did not commit.

Del Africa walked free from Pennsylvania’s state correctional institution, Dallas, on Saturday morning after a long struggle to convince parole authorities to release him. He is the eighth of the nine Move members – five men and four women – to be released or to have died while in prison.

Only one of the nine, Chuck Africa, remains behind bars.

The nine were arrested and sentenced to 30 years to life following a dramatic police siege of their communal home in Philadelphia which culminated with a shootout on 8 August 1978. In the maelstrom a police officer, James Ramp, was killed with a single bullet. Move has always denied that any of its members were responsible.

Brad Thomson, a member of Del Africa’s legal team, said the decision to release him on parole “affirms what the movement to free the Move 9 has been arguing for decades: that their continued incarceration is unjust”.

Delbert Orr Africa upon his release. Photograph: Brad Thomson

Thomson added: “With the release of Delbert, that leaves Charles ‘Chuck’ Africa as the last member of the Move 9 to still be in prison. Chuck went before the parole board last month and we are optimistic that he will be released in the very near future.”

The Guardian told the story of Del Africa and his fellow Move 9 member Janine Phillips Africa in a series of articles on black radicals who have been incarcerated for decades as a result of their activities in the 1960s, 70s and 80s.

Move was formed in Philadelphia as a group of black radicals committed not only to the liberation from racial oppression, in tune with the Black Panther party of the time, but also to environmentalist and back-to-nature ideals. They lived, as they still do today, as a family, taking “Africa” as their shared last name.

Over two years, from prison, Del Africa related his story to the Guardian in emails and a three-hour interview. He recounted how he became engaged in the black struggle when a girlfriend introduced him to the Black Panther Party in Chicago in the late 1960s.

Later, he moved to Philadelphia and drifted into Move. He was inside the Move house in Powelton Village in the summer of 1978 when it came under police siege.

The city, under a notoriously brutal mayor, Frank Rizzo, wanted to evict the group on the grounds that they were a nuisance and an affront to public decency.

When the shootout broke out, police went in with guns and water cannon. Del Africa provided one of the astonishing images of the black liberation struggle when he emerged from the house with his arms outstretched, as if on the cross, while a police officer jabbed a rifle in his neck.

Video footage shows two officers throwing him to the ground and kicking him on the head, which bounces between them like a ball.

Members of move in front of their house in Philadelphia in 1977. Photograph: Leif Skoogfors/Corbis via Getty Images

Africa described the event: “A cop hit me with his helmet. Smashed my eye. Another cop swung his shotgun and broke my jaw. I went down, and after that I don’t remember anything till I came to and a dude was dragging me by my hair and cops started kicking me in the head.”

For six years of his incarceration, Delbert Africa was put in an infamous solitary confinement wing known by prisoners as the “dungeon”. His isolation was imposed because he refused to have his dreadlocks cut – part of the Move philosophy.

He recalled in Guardian interviews how he survived in solitary confinement by developing a black history quiz with other prisoners, which they would play by tapping out messages. Other prisoners joined the game, which asked questions like: when was the Brown v Board of Education ruling in the US supreme court? What year was the Black Panther party founded? Who was Dred Scott? For what is John Brown remembered?

In 1985, when Del Africa had been in prison for almost seven years, tragedy struck again. He learned that Philadelphia police had conducted a second siege on the Move communal home, which was now located in Osage Avenue.

On this occasion, the police dropped an incendiary bomb from a helicopter. The bomb ignited a fire that spread through the overwhelmingly African American neighborhood.

City leaders allowed the fire to rage. Sixty-one houses were razed and 11 people in the Move house were killed, including five children. One of the survivors, Ramona Africa, was badly burned. She was duly put on trial and sentenced to seven years in prison.

One of the children who died was Delisha, Del Africa’s 13-year-old daughter. He told the Guardian how he responded to the news that she had been killed in an inferno: “I just cried. I wanted to strike out. I wanted to wreak as much havoc as I could until they put me down. That anger, it brought such a feeling of helplessness. Like, dang! What to do now? Dark times.”

With the 35th anniversary of the bombing approaching in May, Del Africa is free. At the end of the Guardian’s interview with him, he described how he had managed to endure four decades behind bars.

“I keep staying on the move. Stagnation is the worst thing. I’m on the move, and I hope you are too,” he said.

“We’ve suffered the worst that this system can throw at us – decades of imprisonment, loss of loved ones. So we know we are strong. For all of that, we are still here and I look on that with pride.”