DeafSA, South Africa’s leading deaf association, condemned the presence of the unknown man at the memorial, which was attended by President Jacob Zuma and scores of world leaders including U.S. President Barack Obama.

While dignitaries were addressing the crowd in the 95,000-seat Soccer City stadium, the young, suited man with an official security pass round his neck produced a series of hand signals that experts said meant absolutely nothing.

Besides the bizarre twist to an event that also saw Zuma booed and jeered, his presence on the stage within yards of Obama and Brazil’s Dilma Rousseff raises awkward security questions.

“He was basically gesturing. He didn’t follow any of the grammatical rules and structure of the language. He just invented his signs as he went along,” said Delphin Hlungwane, an official South African sign language interpreter at DeafSA.

“There was zero percent accuracy. He couldn’t even get the basics right. He couldn’t even say thank you,” she told Reuters.

Hlungwane said the ‘interpreter’ also failed to impart to television viewers – as he should have done – that the crowd gave a hostile reception to Zuma, a scandal-plagued leader who faces an election in less than six months.

“You’re supposed to indicate with your facial expressions, even if it’s not an exact sign,” she said. “He didn’t indicate that at all. It just passed him by.”

The hunt is on for the man, whose identity is a mystery to South Africa’s deaf community and the government, which was officially in charge of Tuesday’s ceremony.

The ruling African National Congress (ANC) also professed no knowledge, even though television footage from a party congress a year ago appears to show the same man gesticulating on a stage alongside Zuma.

“I don’t know this guy. He doesn’t work for the ANC. It was a government event. Ask them,” spokesman Jackson Mthembu said.

Zuma spokesman Mac Maharaj said he was checking the reports to try to determine the man’s identity. DM

Photo: India’s President Pranab Mukherjee speaks at the podium as a sign language interpreter (R) punches the air beside him during a memorial service for late South African President Nelson Mandela at the FNB soccer stadium in Johannesburg December 10, 2013. The fake sign language interpreter took to the stage during Tuesday’s memorial for anti-apartheid leader Nelson Mandela, gesticulating gibberish before a global audience of millions and outraging deaf people across the world. Picture taken December 10. REUTERS/Kai Pfaffenbach