The "fake" sign language interpreter at Nelson Mandela's memorial service has reportedly admitted being part of a group of people who killed two thieves by burning tyres around their necks.
Thamsanqa Jantjie, 34, who stood on stage next to President Barack Obama and other world leaders at the ceremony last week, was quoted by a South African newspaper saying that he had been part of a "community justice thing - what you call mob justice".
During the struggle against apartheid, "necklacing" was a particularly brutal method of killing used against blacks suspected of aiding the regime.
In recent years, it has been used more rarely in instances of vigilante justice.
One of Jantjie's cousins and three of his friends told AP that in 2003 he was among a group of people who set fire to tyres placed around the necks of two men accused of stealing a television set. Jantjie acknowledged his involvement in this incident, according to the Sunday Times of Johannesburg.
Other suspects stood trial for murdering the two men in 2006, but no charges were brought against Jantjie because he was found mentally unfit, his cousin and friends said.
Jantjie spent more than a year at a mental health facility, they added, before returning to his home in Bramfischerville, near Soweto.
The Daily Telegraph has established that Jantjie was convicted of theft in 1995 and jailed for three years, although it is unclear whether he served any of that time. There also appears to be an outstanding arrest warrant for a second theft allegation
Jantjie said he was suffering from a schizophrenic episode when he began hallucinating and signing "nonsense" during the four-hour ceremony in honour of Mandela at the FNB Stadium in Soweto.
South African officials have opened an investigation to determine who hired Jantjie as the onstage interpreter for the service and if and how he received security clearance.