A U.K. police investigation into the alleged crash of a drone into a British Airways Airbus A320 aircraft has so far elicited no evidence of a strike and no suspects. The initial probe found no damage to the airplane and a wide area search for suspects and debris has been unsuccessful, London’s Metropolitan Police said Monday. The pilot reported that the front of the aircraft was hit as it was descending over Richmond Park in southwest London at an altitude of about 1,700 feet (518 meters), shortly before landing normally at Heathrow Airport on a flight Sunday from Geneva. The police haven’t yet ruled out an incident and are asking any members of public who may have been in the Richmond area for evidence. They reiterated a warning to drone enthusiasts to avoid operating the devices near airports, in flight paths or in crowded places such as stadiums. “Thankfully the aircraft landed safely, but the incident highlights the very real dangers of reckless, negligent and some times malicious use of drones,” Martin Hendy, head of the Metropolitan Police aviation-policing command, said in a statement. “We continue to work with the Civil Aviation Authority and other partners to tackle this issue and ensure that enthusiasts who fly drones understand the dangers and the law.” U.K. regulators stipulate that users must be able to see their drone at all times, refrain from flying it higher than 400 feet and keep it away from planes, helicopters, airports and airfields. In the U.S., the Federal Aviation Administration requires operators to stay more than five miles (8 kilometers) from airports unless they get permission from air-traffic controllers.