The families of Lolo Sono and Siboniso Tshabalala want answers after South African police reopened the case into their deaths.
It has been alleged the anti-apartheid activists were killed in the 1980's by bodyguards of Winnie Mandela, the ex-wife of former president Nelson Mandela.
Results from tests taken from body samples could take at least two months.
Tania Page reports from Soweto.