(JTA) — Switzerland has opened an investigation into a computer virus linked to Israel that allegedly was used to spy on European hotels hosting the Iran nuclear talks.

There is an open investigation into “political espionage in Switzerland,” Swiss Attorney General Michael Lauber said Wednesday, Reuters reported.

Swiss authorities have searched hotels in relation to the investigation, Reuters reported, citing an aide to Lauber. Three hotels in Switzerland have served as venues for the talks between Iran and six world powers.

The Wall Street Journal reported last week on the Duqu virus, which has been linked to Israel. Each of the unnamed hotels in the Journal report was targeted by a version of the Duqu virus about two weeks before hosting the negotiations.

Israel has rejected accusations that it was involved in spying on the talks or on its allies.

The Moscow lab that discovered the virus, Kaspersky, does not identify Israel by name as being responsible for the virus, which allows the hacker to eavesdrop on conversations and steal electronic files, and could also enable the hacker to operate two-way microphones in hotel elevators, computers and alarm systems. But it does use hints, including the name of the report, “The Duqu Bet.” Bet could be a reference to the second letter of the Hebrew alphabet.

The Duqu virus reportedly is related to Stuxnet, the computer worm that set back Iran’s nuclear program by several months or years by affecting some of its computer systems and centrifuges used to enrich uranium after it was released in 2010. The New York Times reported that it was a joint project of Israel and the United States.