Much of that work is now under scrutiny as a result of the leak of 11.5 million records being pored over by an international coalition of more than 100 media outlets.

Fonseca said in an interview on Tuesday that they are genuine and were obtained through an illegal hack.

Fonseca, on Twitter, describes himself to his more than 19,000 followers as a "lawyer, writer and dreamer." But the modest self-image contrasts with the influential role he has played in Panamanian politics and business.

Until recently, he was president of the governing Panamenista party and served in the Cabinet of President Juan Carlos Varela as a special adviser. He was forced to resign in February after the offices of the Mossack-Fonseca affiliate in Brazil were raided and several managers arrested as part of the investigation into bribes paid to politicians by companies doing business with the state-run oil giant Petrobras.

"In Panama they're seen as too big to fail," said Miguel Antonio Bernal, a law professor at the University of Panama.

His brother heads Panama's civil aviation society and his son is consul general in Dubai.

Fonseca's fiction, for which he's won Panama's top literary prize, comes straight from the shady, smoke-filled rooms of political bosses.

In 2012, he published "Mister Politicus," a novel which he says is partly based on his life experience and which he describes on his website as "detailing the convoluted scheming of unscrupulous officials to gain power, and from there, satisfy their detestable ambitions."

Fonseca has some strong pro-democracy credentials in a country whose 1968-1989 military dictatorship spurred the growth of Panama's offshore banking industry. He played a critical role denouncing the 1993 slaying of a Roman Catholic priest, a move that led to the creation of a truth commission to investigate the dictatorship's crimes.

Far less is known about Jurgen Mossack, his partner, who has so far not spoken up.

Mossack's father, Erhard Mossack, was a member of the armed wing of Germany's Nazi party, according to US Army intelligence files gathered by the International Consortium of Investigative Journalists, which has been coordinating the investigation into the law firm and its leaked documents. The AP has been unable to verify the reports.

Fonseca said he had no knowledge about any Nazi ties in his longtime partner's family. He said Erhard Mossack came to Panama in the 1960s, when Jurgen was 13, and worked as an executive at Lufthansa airlines.

"He's not comfortable around the cameras," Fonseca said. "He's a German."

Fonseca said he is speaking out to defend his firm's reputation and is confident there will be no legal fallout from the leak because his company has been ahead of legislation in implementing tighter due diligence controls.

He said he has no idea how the documents - passport photos, stock certificates and emails - ended up in the hands of journalists but said it was unlikely an inside job. Rather, he suspects the company was targeted by hackers from abroad because it's been so successful beating out competitors in the US and elsewhere.

"I think it will be material for my next novel," he said.