BERLIN – German federal prosecutors on Monday dropped a much-criticized treason investigation of two journalists who had reported on secret plans to expand online surveillance in Germany.

Prosecutors notified website Netzpolitik.org in July that its founder, Markus Beckedahl, and fellow journalist Andre Meister were under investigation — prompting widespread criticism from free-speech advocates. The website specializes in covering online privacy and digital culture.

Justice Minister Heiko Maas questioned the decision to open a treason probe, which is a rare move in Germany. Last week, he fired chief federal prosecutor Harald Range after the two clashed over public allegations by Range of political interference, which the minister denied.

On Monday, the federal prosecutor’s office said it is closing the case because it believes the leaked documents the website’s reports were based on were not a “state secret” and other conditions for treason charges also weren’t fulfilled.

The probe, which was opened following a criminal complaint filed by Germany’s domestic intelligence agency, also targeted the unidentified source of the leaked documents. Monday’s statement said that investigating the source or sources for violating secrecy will now be a matter for lower-ranking local prosecutors.

Beckedahl said the decision to drop the probe was not enough.

“We want to know precisely whether we were subject to surveillance measures during the almost three-month investigation,” he said in a statement.

Beckedahl added that he hopes the case will motivate authorities to improve protection for whistleblowers in Germany.

Chancellor Angela Merkel’s spokesman, Steffen Seibert, said the government wouldn’t comment on the prosecutors’ decision but stressed its commitment to press freedom.

The head of the German Federation of Journalists, Michael Konken, said that “the attempt to criminalize the journalists concerned has failed spectacularly.”

However, he said, the rules on treason cases should be changed to exempt journalists from prosecution.