The investigative network Correctiv has urged Germany's federal government to scupper Hamburg's investigation against reporter Oliver Schröm, the editor-in-chief of Correctiv's German-language team, and instead track down tax offenders.

"Tax robbery is a crime. Journalism is not," wrote the network in an open letter initiated late Tuesday and addressed to Justice Minister Katarina Barley and Finance Minister Olaf Scholz, himself a former Hamburg mayor.

In October, Correktiv and other European media outlets accused banks of draining €55 billion ($63 billion) from national treasuries in a years-long tax scam.

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Correktiv and the other media outlets, including France's Le Monde and German public broadcaster ARD, reported that cum-ex investors used rapid-fire buying and selling of companies' shares to disguise true ownership and thereby claim multiple tax rebates.

Correctiv said the Hamburg Prosecutor's Office investigation against Schröm stemmed from a Swiss case against the Swiss bank Sarasin.

"Sarasin, which is deeply entangled in the scandal surrounding the stolen taxes, alleges Oliver Schröm abetted a whistle-blower inside the bank in disclosing confidential information," said Correctiv. "This accusation is absurd."

Correctiv added that Schröm had begun his probe in 2014 to expose a "massive grievance in our society."

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Hamburg state prosecutions spokeswoman Nana Frombach said Hamburg had since May adopted the Swiss case because Schröm lived in Germany's northern harbor-side city-state.

Attack on freedom of the press

Frank Überall, chairman of the German DJV journalists' federation, accused Hamburg of making itself a "sidekick" to Swiss judicial authorities, saying the case amounted to an attack on press freedoms.

Without whistle-blowers there was no chance to expose cum-ex-like scandals, said opposition Greens federal parliamentarian Gerhard Schick.

Late last month, the European Parliament heard proposals from Schröm for incorporation into a parliamentary resolution.

Correctiv, based in Berlin and Essen in the Ruhr district of western Germany, was formed in 2014 as a non-profit private limited company — backed by donations — to uphold journalism's public watchdog role as print-media faced losses in advertising revenues to internet concerns.

Research findings are forwarded to established radio and television stations.

ipj/sms (dpa, epd, AFP)