JOHANNESBURG (AP) — The man accused of faking sign interpretation while standing alongside world leaders like US President Barack Obama at Nelson Mandela’s memorial service said Thursday he hallucinated that angels were entering the stadium, has schizophrenia and has been violent in the past.

Thamsanqa Jantjie said in a 45-minute interview with The Associated Press that his hallucinations began while he was interpreting and that he tried not to panic because there were “armed policemen around me”. He added that he was once hospitalised in a mental health facility for more than one and a half years.

The statements by Jantjie also raise serious security issues for Obama, other heads of state and United Nations Secretary-General Ban Ki-moon who stood next to Jantjie as they made speeches at FNB Stadium in Soweto, Johannesburg’s famed black township. The ceremony honoured Mandela, the anti-apartheid icon and former president who died on December 5.

A South African deputy Cabinet minister, Hendrietta Bogopane-Zulu, later held a news conference to announce that “a mistake happened” in the hiring of Jantjie. However, many questions remain, including who in the government hired the company that contracted Jantjie, how much money the government paid the company and Jantjie’s own involvement with the company — and even whether it really exists.

AP journalists who visited the address of the company that Jantjie provided found a different company there, whose managers said they knew nothing about SA Interpreters. A woman who answered the phone at a number that Jantjie provided confirmed that she worked at the company that hired him for the memorial service but declined comment and hung up.

Government officials said they have tried to track down the company that provided Jantjie but the owners “have vanished into thin air”, said Bogopane-Zulu, deputy minister of Women, Children and People with Disabilities.

She apologised to deaf people around the world who were offended by Jantjie’s incomprehensible signing and said an investigation is under way to determine how Jantjie was hired and what vetting process, if any, he underwent for his security clearance.

The deputy minister said the translation company offered sub-standard services and the rate they purportedly paid the translator, US$77 a day, is far below the usual rate of up to US$164 an hour.

Ordinarily, sign language interpreters in South Africa are switched every 20 minutes to maintain their concentration levels, she said. Jantjie was on the stage for the entire service that lasted more than four hours.

The deputy minister declined to say who in South Africa’s government was responsible for contracting the company that provided the bogus translator, or how those rules were flouted.