After 52 years,
Their bodies were crammed into four unmarked graves on rough ground in a bottom corner of cemetery beside a road in the capital Pretoria.
The exhumation will allow Tyopo to give his father a proper ancestral burial -- one small attempt at healing the wounds of decades of state violence and repression that marked South Africa until the end of white-minority rule in 1994.
"For so long we didn't know where the body was. We had no information. I feel happy," Tyopo, who was just four when his father was hanged, told AFP.
His father Vulindlela was one of a group of 12 activists from the Pan-African Congress (PAC), an anti-apartheid party that was banned by the segregationist government.
All were hanged -- including four other family members -- for the murder of five white people in an attack in Eastern Cape province.
This week, forensic anthropologists equipped with trowels, spades and brushes excavated a hole two metres deep, gradually revealing skulls -- some very damaged -- femurs and tibias, as well as the handles and steel nails from disintegrated coffins.
"The fingers, the ribs, the vertebrae have been reduced to dust,"Kavita Lakha, one of the anthropologists, said.
"But for the families, to be able to identify a head or a major bone, that is better than nothing."
Anti-apartheid activists hanged under the regime were often buried in paupers' graves without headstones.
Their relatives could not attend the burial and were never told where their loved ones lay.
Only the cemeteries' neat registry books, now yellow and faded, recorded the name and location of each corpse.
'Punishment beyond death'
The bodies even remained property of the state, inflicting a "final punishment beyond death," said Madeleine Fullard, head of the Missing Persons' Task Team.
"This is one step in the family coming to some sense that their journey is ending," she added.
"We are not necessarily looking to heal... but certainly many of the families feel that once they are able to bury the remains, they have done what they can to make right what was done wrong."
At the Rebecca Street cemetery in Pretoria, the hanging victims were buried in the "Africans and paupers" section, far from the peaceful jacaranda-lined avenues reserved for white Afrikaners.
The government-organised exhumation was the first of its kind in South Africa, which plans to unearth scores of bodies of political prisoners executed between 1960 and 1990.
Justice Minister Michael Masutha, who attended the graveside scene, said the hangings and treatment of the bodies reflected the criminal justice system at the time.
The exhumation policy follows the recommendations of the Truth and Reconciliation Commission, established in 1996, which revealed the full horrors of crimes committed during apartheid.
South Africa has been assisted in the task by Argentinian authorities, experienced in handling bodies of victims from the country's dictatorship.
Now the families hope to re-bury the remains early next year in the Eastern Cape, in line with tradition that demands a correct burial to protect the surviving family.
"Every movement has a responsibility to look after its own soldiers," said Phillip Dhlamini, national PAC chairman.
"Where your fighters are captured by the enemy, there will be no peace until their remains are returned to you. So this is the first step towards a lasting peace in this country."