The reopened inquest into the 1982 death of anti-apartheid activist Dr Neil Aggett has found that he did not die by suicide, but was killed by the police while in custody.

On Friday, Judge Motsamai Makume handed down judgment in the inquest that spanned two years.

Aggett, who was 28 at the time, was found hanging in his cell at the infamous John Vorster Square police station, now known as Johannesburg Central, after being detained there for 70 days on suspicions of treason.

A 1982 inquest chaired by Magistrate Pieter Kotze cleared the apartheid government and ruled his death a suicide.

In his judgment, Makume found that Kotze was biased and not interested in finding out what had happened to Aggett, but rather why he had killed himself.

"Dr Neil Aggett did not commit suicide. He was killed by the members of the security branch. When Neil didn’t regain consciousness (after he was tortured), they took him back to his cell, propped him up and hanged him," Makume found.

After Aggett's death, members of the security branch even visited his family home in the Western Cape to find evidence that corroborated the claim that Aggett had killed himself.

"If they were convinced that he had committed suicide, why did they go all the way to the Western Cape to find evidence that wasn’t there?" Makume asked.

The judge said he was appalled by how Kotze had ignored testimony that Aggett was tortured on numerous occasions and had even filed a complaint.

In one incident, just days before his death, he was interrogated for 62 hours.

"The finding that Neil consented to 62 hours of sleep deprivation boggles my mind," said Makume.

He said that the National Prosecuting Authority (NPA) should pursue criminal charges against those involved in Aggett’s death.