A man and woman arrested in connection with drone sightings that grounded flights at Gatwick Airport have been released without charge.
The 47-year-old man and 54-year-old woman, from Crawley, West Sussex, had been arrested on Friday night.
Their release came as Sussex Police said they were relying on eye witnesses and there may have been no “genuine drone activity in the first place”.
Det Ch Supt Jason Tingley said no footage of a drone had been obtained.
He said there was “always a possibility” the reported sightings of drones were mistaken.
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However, he said officers were working on a range of information from members of the public, police officers and staff working at Gatwick who had reported seeing a drone.
A damaged drone found close to the airport on Saturday was being forensically examined, he said.
Det Ch Supt Tingley said it was “a working assumption” the device could be connected to their investigation, but officers were keeping “an open mind”.
“We are also going through many reports of sightings of drone activity over the last few days,” he said.
“We are meticulously going through that information to see if that produces any other further lines of inquiry, and also where we may focus our efforts in terms of house-to-house inquiries, CCTV footage, and any other information that will help us work through this investigation.”
Flights were suspended for more than 36 hours when a device was first spotted close to the runway on Wednesday night.
Det Ch Supt Tingley said the arrested man and woman had “fully co-operated” with inquiries after information was received from a member of the public.
Talking about the disclosure of their personal details in the press, he said he was satisfied their arrest was lawful, and stressed that officers would never reveal such information.
He added: “We would not have chosen in any event to provide that information to anyone… and one might say that’s probably hindered us in terms of how quickly we’ve been able to get to a resolution in terms of them being released from custody.”
Gatwick Airport Limited has now offered a £50,000 reward through Crimestoppers for information leading to the arrest and conviction of those responsible for disrupting flights.
About 1,000 aircraft were either cancelled or diverted, affecting about 140,000 passengers, during three days of disruption.
On Sunday the airport said it was operating as normal but there had been “some knock on effect”. Passengers have been urged to check with their airline for the latest information.
Authorities finally regained control over the airfield early on Friday after the Army deployed unidentified military technology.
It is believed that the Israeli-developed Drone Dome system, which can jam communications between the drone and its operator, was used.
However, experts have said it does not enable the person responsible to be tracked down and captured.
John Murray, professor of robotics and autonomous systems at the University of Hull, said it could only “take the drone out of the sky”.