New Jersey police have opposed the release of Sundiata Acoli, who killed a state trooper more than 40 years ago, since he became eligible for parole in 1992

This article is more than 3 years old

This article is more than 3 years old

A former Black Panther who turns 80 next month has been denied release from prison and ordered to wait 15 years before seeking freedom again.

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Sundiata Acoli is serving a life sentence for the 1973 murder of a New Jersey state trooper during a shootout in which Assata Shakur was also arrested. Shakur escaped in 1979 and fled to Cuba, where she was granted political asylum.

New Jersey state police have actively opposed Acoli’s release since he first became eligible for parole in 1992. But the decision still shocked his supporters.

“This is a punch to the gut,” said Soffiyah Elijah, an attorney who represented Acoli for decades and visited him days before he learned of his latest denial on 21 November.

Facebook Twitter Pinterest A photo of New Jersey state trooper Werner Foerster. Acoli ‘expressed regret and remorse’ about his involvement in Foerster’s death. Photograph: Tim Larsen/AP

The move comes after a panel of New Jersey judges ordered the board in 2014 to “expeditiously set conditions” for Acoli’s release. The court cited his good behavior since 1996, and argued the board had ignored a psychologist’s 2010 testimony that Acoli “expressed regret and remorse about his involvement” in the state trooper’s death. The expert determined Acoli posed a “low to moderate risk” of reoffending.

In February, a higher court overturned the order in a decision welcomed by state police as “a victory for law enforcement”. This prompted a new parole board hearing in June that led to the denial.

In a letter to supporters, Acoli said the June hearing focused “primarily about the events on the turnpike and almost nothing about my many positive accomplishments”. Acoli wrote that parole board members asked him, “Aren’t you angry that they broke Assata out of prison instead of you?” He responded that “I don’t or wouldn’t wish prison on anyone.”

Most of Acoli’s four decades in prison have been spent at “supermax” federal penitentiaries in Marion, Illinois, and Fort Leavenworth, Kansas, where he was held 23 hours a day in his cell under high security. He is now incarcerated at a federal prison in Cumberland, Maryland.

“They are determined to bury him alive,” Elijah told the Guardian. “And we are equally determined to get him out.”