JOHANNESBURG, South Africa - Just when it seemed the scandal over the bogus sign language interpreter at Nelson Mandela's memorial had run its course, a cousin and three friends say he was part of a mob that accosted two men found with a stolen television and burned them to death by setting fire to tires placed around their necks.

Thamsanqa Jantjie never went to trial for the 2003 killings when other suspects did because authorities determined he was not mentally fit to stand trial, the four said Monday. They spoke on condition of anonymity because of the sensitivity of the fake signing fiasco, which has deeply embarrassed South Africa's government and prompted a high-level investigation.

Their account of the killings matched a description of the crime and the outcome for Jantjie that he himself described in an interview published by the Sunday Times newspaper of Johannesburg.

"It was a community thing, what you call mob justice, and I was also there," Jantjie told the newspaper.

Jantjie was not at his house Monday, and the cousin said that Jantjie had been picked up by someone in a car Sunday and had not returned. His cellphone rang through to a message saying Jantjie was not reachable.

Instead of standing trial in 2006, Jantjie was institutionalized for a period of longer than a year, the four said, and then returned to live in his poor township neighborhood on the outskirts of Soweto. At some point after that, they said, he started getting jobs doing sign language interpretation at events for the governing African National Congress party.

Jantjie said that he has schizophrenia, hallucinated, and believed he saw angels while gesturing incoherently just three feet away from President Obama and other world leaders at the memorial last Tuesday. Signing experts said his arm and hand movements were mere gibberish.

In the interview Thursday, Jantjie said he had been violent "a lot" in the past, but declined to provide details. He blamed his behavior on his schizophrenia, saying he was institutionalized for 19 months, including a period during 2006.