Before the proceedings got underway, Peter and Linda Biehl shook hands with the parents of Mzikhona Mofemela, Ntobeka Peni, Vusumzi Ntamo and Mongezi Manqina, who are serving 18-year prison terms for their role in the mob-attack on the 26-year-old Fulbright scholar.
Pan Africanist Congress leaders are expected to meet the Biehls privately later on Tuesday.
The Biehls sat silently, showing no emotion, as the four PAC members arrived at the packed venue for their Truth and Reconciliation Commission amnesty hearing. They are not expected to oppose their amnesty applications.
Relatives of the men, PAC supporters and journalists were among the audience watching the proceedings.
Biehl's parents were seated in the front row of the audience flanked by Melanie Jacobs, one of Biehl's former room-mates, and Rolene Miller, who manages the Mosaic Programme, a project supported by the Biehl Foundation.
The four applicants, three of whom were wearing new sneakers, looked uneasy as press photographers crowded around them at the start of the proceedings.
Peni, a former chairman of the Pan Africanist Students' Organisation's Guguletu branch, has said the killing was carried out with the approval of Paso's regional executive.
Explaining the political motivation for the murder: "I rose against the government and in the process a white woman was killed."