An IT worker at the Geneva offices of Mossack Fonseca, the offshore law firm at the centre of the Panama Papers scandal, has been arrested in the hunt for the whistleblower behind the biggest ever leak to journalists.

Early last year, an individual using the alias John Doe approached the German newspaper Süddeutsche Zeitung, offering data from the internal files of Mossack Fonseca. The leak led to the resignation of the Icelandic prime minister in April this year and sparked international protests over the use of tax havens by financial and political elites.

“A procedure has been opened by the public ministry of Geneva following a complaint made by Mossack Fonseca,” a spokeswoman for the city prosecutor confirmed on Wednesday afternoon. She said further information would follow in due course. The person arrested has not been named.

Uncertainty surrounds the reasons for the arrest. Süddeutsche Zeitung believes that the person arrested is not the newspaper’s source. Bastian Obermayer, who jointly led the investigation at the German paper, told the Guardian: “According to our information this is not John Doe”.

According to our information the #mossackfonseca IT person arrested in Geneva is not #panamapapers" source "John Doe" @ICIJorg @f_obermaier — Bastian Obermayer (@b_obermayer) June 15, 2016

The source has not revealed their identity but has offered to cooperate with law enforcement.

Mossack Fonseca is accusing its employee of information theft and breach of trust, a lawyer for the firm told the Swiss newspaper Le Temps.

Asked if the accused was John Doe, lawyer Thierry Ulmann said: “All hypotheses are open. What we know is that data was taken via his computer in Geneva and that this IT worker had full access privileges.

“It’s on this basis that we have filed a complaint for data theft and breach of the law firm’s trust. Very detailed investigations are being undertaken by Geneva police to analyse the digital traces and shed light on this theft of data.”

The IT worker’s two lawyers, Thomas Barth and Roman Jordan, said their client “denied all of the accusations against him”.



A search is understood to have been conducted at Mossack Fonseca’s Geneva office and IT equipment has been seized.

The case is being overseen by magistrate Claudio Mascotto, who previously intervened over the Panama Papers. In April he oversaw a swoop on the Geneva Freeport, during which an £18m Modigliani painting allegedly looted by the Nazis was seized. The identity of the true owners of Seated Man with a Cane, currently the subject of a legal battle, was revealed by the Mossack Fonseca leak.

Published on 3 April 2016, the Panama Papers revealed the tax-haven companies used by 12 heads of state, more than 100 politicians and their relatives, political donors, companies put under sanction by the US and Europe, convicted criminals, and drugs and arms dealers.

More than half of the 214,000 companies whose details were leaked in the cache of 11.5m documents were incorporated in the British Virgin Islands.

The data was passed to the International Consortium of Investigative Journalists in Washington and shared with media organisations around the world including the Guardian and the BBC.