What’s behind the surge in mysterious drone sightings over New Jersey, Massachusetts and other states?

A month after mysterious drones were first reported over New Jersey, authorities are still trying to determine where they are coming from as sightings increase in frequency and spread into neighboring states.

Much is still unknown about the drones, but the FBI, Homeland Security and the White House have all stated there is no evidence they were launched by foreign adversaries or pose safety risks. Many are believed to be manned aircrafts that are being flown lawfully.

Deniz Erdogmus, a Northeastern University drone expert and chief technology officer of the university’s Kostas Research Institute, says there is still much to learn about the mystery drones before jumping to conclusions.

Who is operating the drones?

The Kostas Research Institute studies drones to improve security and resilience. Its Unmanned Aerial System (UAS) Flight Facility includes specialized testing areas for drone performance and antenna systems and supports collaboration with industry and government.

As the situation unfolds, Erdogmus suggests the mystery drones might be operated by a private company aiming to “test the limits of what they can do.”

“My best guess is that these are private drones that might be operating legitimately,” says Erdogmus, a distinguished professor in the College of Engineering.

Still, he says, the lack of accountability is puzzling.

“After one month of being in the news, why are they not saying, ‘Sorry for the inconvenience. That was just us doing business legally according to regulations,'” Erdogmus asks.

On Saturday, Massachusetts Gov. Maura Healey took to social media to address drone sightings in her state, saying she is “monitoring the situation closely.”

“Drone operators should adhere to all applicable laws, regulations, and appropriate operating procedures, ensuring the safe and responsible use of drones,” she said.

How big are the drones?

These aren’t your typical hobby drones used for recreational purposes—they are reportedly up to 6 feet in diameter and match the dimensions of commercial-grade models.

Erdogmus says drones of this size are typically used for the transportation of items. Amazon, for example, has been using drones for deliveries in select markets.

Under FAA regulations, drones of this size should be transmitting signals that identify their position through the agency’s Remote ID rule, Erdogmus says, though it’s possible that these types of drones could be sharing their ID, but still be undetected by typical flight tracking systems.

Following the drone sightings in New Jersey last month, the FAA issued a no fly zone over Picatinny Arsenal Military Base and Trump National Golf Club Bedminster—areas near where the drones were reported.

Erdogmus suspects that more no fly zone orders may be issued in critical areas if drone sightings continue to spread.

Should the drones be shot down?

President-elect Donald Trump and others say the drones should be shot down, but Erdogmus says there are other ways to intercept them for intelligence-gathering purposes.

For example, another drone equipped with a net could be used to jam up their propellers, he says. Also, the mystery drones could also be taken down through a cyber attack.

Either of these methods would be better and less dangerous than shooting at the drones, Erdogmus says.

“There are a number of methods to disable drones without actually firing bullets at them,” he says. “To just start shooting things down is a little reckless.”

If the drones are in fact being operated by benign actors, Erdogmus believes investigators will eventually be able to pinpoint where they originated from.

“They could be legitimate government operations,” he says. “They could be legitimate private operations,” he says. “In both cases, I think there might be information that’s not yet out in the news to know what’s going on.”

This story is republished courtesy of Northeastern Global News news.northeastern.edu.