South Africa will open a new inquest into the 1977 death in police custody of iconic anti-apartheid figure Steve Biko, state prosecutors announced on Wednesday.

The inquest will be officially registered in court on Friday, the anniversary of Biko’s death nearly a half-century ago.

South African authorities have recently opened new inquests for other anti-apartheid leaders and activists who died in police custody or in suspicious circumstances during the brutal system of racial segregation, although they’ve been criticised for waiting so long to do so.

They include the 1967 death of Nobel Peace Prize winner Albert Luthuli, the 1981 killing of lawyer Griffiths Mxenge and the 1985 killings of a group of activists known as the Cradock Four.

Biko was at the forefront of the Black Consciousness Movement that emerged in South Africa in the 1960s in opposition to apartheid.

He was arrested by apartheid security forces in August 1977 near the town of Grahamstown on the south coast and was allegedly beaten and tortured while kept shackled and naked at a police station and later the local police headquarters by the notorious police Special Branch.

On September 11, 1977, after more than 20 days in custody, he was loaded unconscious into a police vehicle and driven more than 1,000 kilometres (621 miles) to a prison hospital in Pretoria, where he died the following day in a cell, still naked and with his legs shackled. He was 30.

The cause of death was recorded as brain injuries and kidney failure. An inquest later that year that has been largely dismissed as a cover-up found that Biko banged his head against the wall in a scuffle with police officers.

Dozens of activists died in police custody during apartheid and inquests at the time generally exonerated the security forces of any blame.

After apartheid officially ended in 1994, South Africa held a Truth and Reconciliation Commission in an attempt to investigate and expose the crimes of apartheid. Some police officers were granted amnesty for their actions, but many were not.

Yet hardly any of those implicated in killings and other crimes were prosecuted in the years after apartheid, and successive post-apartheid South African governments have been criticised for allowing the cases to slip away.

President Cyril Ramaphosa has announced an inquiry into allegations that investigations were intentionally blocked.

The men known as the Cradock Four were believed to have been abducted, tortured and killed by police 40 years ago. A new inquest into their deaths opened in June, but the policemen implicated in their killings have all died without ever being prosecuted.

It’s not clear if any of the police officers implicated in Biko’s death are still alive. South Africa’s National Prosecuting Authority said the new inquest into Biko’s death 48 years later was an effort “to address the atrocities of the past and assist in providing closure to the Biko family and society at large.”

Biko inspired a hit song by musician Peter Gabriel that became an anti-apartheid anthem, and actor Denzel Washington starred as Biko in the 1987 film “Cry Freedom.”

• An AP report