French authorities on Wednesday arrested a three-man Al Jazeera news crew accused of flying a drone from a Paris park without a license. But they appear to be no closer to solving the months-long mystery of who has been deploying unmanned aircraft over landmarks and sensitive security sites at night.
At least five drones were spotted in the night sky Tuesday and early Wednesday, buzzing major tourist venues such as the Eiffel Tower and the Place de la Concorde, according to international news agencies in the French capital.
French media have also reported sightings of drones over nuclear plants, military installations and heavily guarded sites including the U.S. Embassy and the Elysee Palace, which is home to French President Francois Hollande.
The three Al Jazeera journalists were detained when police found them operating a drone in the Bois de Boulogne woods along the western edge of Paris, Agnes Thibault-Lecuivre, a spokeswoman for the city prosecutor's office, told France-24 television.
Flying any aircraft below an altitude of 6,000 meters (19,700 feet) is prohibited by law without a license and punishable by up to a year in prison and a fine of about $85,000. No nighttime drone flights are allowed even by licensed operators.
The arrested journalists were not identified by Thibault-Lecuivre, but the Associated Press reported that they were foreign nationals ages 70, 54 and 36.
A statement from the global news network's headquarters in Doha, Qatar, said the trio had been filming a report on the mysterious nighttime sightings of drones.
Britain's Sky News observed in its report that even under the stepped-up security measures in place in Paris since the Jan. 7 terrorist attack on the offices of a satirical magazine, "authorities have been unable to identify the operators of the drones."
Authorities are also unsure whether the illegal surveillance incidents are connected and don't know the operators' objectives, Euronews said on its website.
"What we've seen since these drone flights over nuclear plants began at the end of October is that there are no projectiles. These drones are not crashing into the ground either," military affairs writer Jean-Marc Tanguy told Euronews. "So these drones are being used by people who know how to operate them, though we can't decipher whether we're talking about professionals or geeks."
Authorities have said an investigation is underway.
French government spokesman Stephane Le Foll told journalists Wednesday that the drones weren't considered a security risk.
"There is nothing to worry about," he told a news briefing.