The South African government says it is investigating how the signer for the deaf at Nelson Mandela's memorial service came to be hired.
The announcement follows a report by private South African TV channel eNCA that the interpreter had faced violent criminal charges in the past, including murder and kidnapping.
Thamsanqa Jantjie caught the attention of media after organisations for the deaf accused him of being an imposter and signing gibberish throughout the memorial service.
The TV channel's report alleged that Mr Jantjie faced a string of criminal charges between 1994 and 2003, but it was unclear how the cases were resolved because the relevant judicial files were "empty."
A government spokesperson said it was investigating whether a security lapse had taken place in his hiring and whether he is the professional signer he claims to be.
Mr Jantjie stood just feet from US President Barack Obama and other world leaders at Tuesday's event at the Soweto World Cup stadium, outside Johannesburg.
The interpreter told media he is a qualified signer and claims he was confused on stage because he had a schizophrenic attack.