Police in the UK have said that they believe there was more than one drone involved in an incident that grounded flights at Gatwick for 36 hours.
Assistant Chief Constable Steve Barry, from Sussex police, said officers are working on the theory there is more than one drone, although the last sighting was at around 10pm on Thursday.
He said: "We're working on the assumption that there was more than one drone operating around Gatwick in the last 48 hours.
"In terms of how many perpetrators, there's a number of lines of enquiry, there's an ongoing investigation, we're pursuing that trying to find out who has been responsible for this really malicious criminal behaviour."
He said there had been no opportunities to shoot down the drones, explaining: "We have to consider whether it's safe to do so, it has to be dynamically assessed at the time, in terms of the risk, and we have to assess whether it's going to be efficient, effective, how likely it's going to be we're going to be able to take the drone out.
Mr Barry said the drones could have been operated from a fair distance away, but police are focusing on "likely locations in and around the airport".
Addressing the problems with identifying suspects, he added: "It's the remoteness between the officer and the drone and over the whole area around Gatwick does make it really difficult to link the drone to the operator."
- Press Association