Many of the documents relating to the Crypto company spy scandal will remain under lock and key, says the deputy head of the Swiss Federal Intelligence Service (FIS).

Even the intelligence services don’t know what happened to a file that went missing in 2014, according to a Swiss public television SRF report.

It is alleged that the German and United States intelligence services spied on a host of other countries after they took over the Crypto business in 1971. Hundreds of thousands of messages between governments, embassies and military commands from more than 100 countries could be monitored up until 2018 when the espionage is said to have stopped.

The revelation, uncovered by a media investigation, has rocked Switzerland’s image as a neutral nation. The Swiss government has appointed a former judge to conduct an inquiry into the case.

The investigation by SRF, the Washington Post and German broadcaster ZDF, relied on 280 pages of previously secret documents. But Jürg Buhler of the Federal Intelligence Service (FIS) says that other sensitive documents will not see the light of day in the immediate future.

This includes details of a Swiss police investigation in the 1990s that Bühler himself led. The probe was dropped without charges being laid.

“There is still a lot of valuable personal data in these files,” he told SRFExternal link. “They contain reports from foreign partners that are subject to [official secrecy] protection and protocols from parliamentary commissions that we cannot open at the moment.”

The SRF programme Rundschau had previously tried to obtain documents in 2014, but a key file disappeared and has still not been located. Even FIS says it does not know where the file is.

Bühler said that the Swiss intelligence service had only recently heard about the missing file and hoped that it would show up at some stage.

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