An otherwise peaceful suburban neighborhood in Washington Township, Pa., began experiencing a series of explosions this past spring and summer. Homemade bombs were blowing up in front yards. Nails were raining down from the sky. Windows were left riddled with marks, as if they had been shot at.
For a while, the police were mystified. They could find no clues to the identity of the bomber, and they were confused about how the perpetrator could leave no footprints, tire tracks or DNA behind.
Only after a resident’s security camera caught a glimpse of what was going on did they crack the case. The perpetrator, it turns out, was a drone, one that the authorities say was controlled by a man who is now behind bars, accused of serious felonies.
Drones pose novel and difficult problems for law enforcement. They are widely available, lightly regulated and can be flown remotely by an operator far away from the crime scene. They have already been put to a host of nefarious uses, from smuggling contraband into prisons to swarming F.B.I. agents who were preparing for a raid. And local and state authorities are restricted by federal law from intercepting drones in flight, potentially even when a crime is in progress, though experts say that has yet to be tested in court.
“The use of drones by criminal groups is appealing in part because drones are harder to catch,” said Arthur Holland Michel, co-director of the Center for the Study of the Drone at Bard College. “They create all kinds of headaches for law enforcement.”
In the Pennsylvania case, the authorities arrested Jason Muzzicato, 43, who is accused of dropping homemade bombs onto his ex-girlfriend’s property. He has been indicted on charges related to making explosives and possessing firearms, but the only charge concerning his delivery method has been unlawful operation of an unregistered drone. He is scheduled to appear in court Dec. 9.
“At state level, regulation has been very piecemeal or reactive to specific cases, whether criminal or otherwise,” said Hillary Farber, a law professor at the University of Massachusetts School of Law who studies the legal issues surrounding drones. “The charges seemed to miss the heart of the issue of how he was using the drone and how it was posing a threat to another person.”
Drones have been widely available to the general public for about five years, and they are already everywhere. The Federal Aviation Administration counts almost 1.5 million registered commercial and recreational drones in the United States, which does not account for the many unregistered or homemade drones.
There have long been concerns about the use of drones for smuggling. The Border Patrol caught two people flying 28 pounds of heroin over the border near Calexico, Calif., in 2015. In July, a man pleaded guilty to attempting to use an unregistered drone to smuggle a bag of marijuana into Autry State Prison in Pelham, Ga.
What drones see can be as worrisome as what they carry. In 2017, a Utah couple was charged with voyeurism for using a drone to spy on people in their bedrooms and bathrooms. One victim chased the drone to a parking lot, found a memory card full of illicit images and turned it over to the police.
When a drone is flown in a crime, it leaves the authorities little to go on — unless they are able to get hold of the machine.
“Drones have a wealth of very valuable forensic evidence to analyze the classic ‘who, what, when, where, why and how,’” said David Kovar, one of a small number of specialists in the new field of drone forensics.
Mr. Kovar and the company he founded, URSA, provide technology to law enforcement officers and train them how to capture data from drones that can establish where and when it was flown and by whom.
But investigators may not be able to tap such expertise in every case. “Unless it is a very high-stakes investigation, it’s unlikely they will call in an expert,” Mr. Holland Michel said.
And even if a drone is recovered and dissected by experts, if it is homemade, it may prove impossible to trace to an owner.
Drones are not easy to detect in flight, as the Secret Service found when one flew unnoticed over the White House grounds and crash-landed on the lawn in 2015.
Audio sensors can listen for the distinctive sound of a drone, but that method does not work well in urban areas, and a drone’s sound signature can be altered by changing its propellers. Cameras have limited reach and may not be able to tell a drone from a bird. Commercially manufactured drones are typically made largely of plastic and run on battery power, so they do not give off much heat or show up strongly on radar. Picking up a drone’s radio signal is considered the most reliable way to detect one — but that does not mean the drone is easy to catch.
Then there is the question of who has the authority to do something about a drone that may be up to no good.
The F.A.A. has primary authority over what happens in the air, and it sets the rules for drone use across the country. A flight is generally legal as long as the drone is registered and displays its registration number, weighs less than 55 pounds, stays within 400 feet of the ground and avoids crowded places like stadiums or restricted areas like airports.
All reported sightings of drones flying in restricted airspace are recorded by the F.A.A., and the agency can impose civil penalties on those who break the rules, according to a spokeswoman. But the F.A.A. does not have criminal enforcement authority, and though it requires drones to be registered, it depends on the honor system.
“It’s not like a car — it’s not necessary to register at sale,” Mr. Holland Michel said, adding, “A criminal will not register a drone.”
Local and state authorities are often the ones dealing with crimes committed using drones, but their authority is limited. They have no power to charge suspects specifically for drone-use violations.
According to F.A.A. sightings data, when the police in Huntsville, Ala., were notified by a pilot in June that a drone had been spotted in restricted airspace, the police “did not know whether or not that was their jurisdiction, nor what to do about it if it was.”
All the police can usually do, experts said, is use the drone as evidence — if they can get hold of it — and charge suspects for the crimes that the drone was used to commit.
“The legal landscape is chaotic when it specifically comes to drones,” said Mr. Kovar, the forensics expert. “Using existing laws such as voyeurism or harassment sidesteps this issue.”
What about using jamming systems or other technology to interfere with drones in flight or keep them from flying where they do not belong? The only agencies allowed to do that are the federal departments of Defense, Justice, Energy and Homeland Security. For everyone else, it is illegal in all but the most exceptional circumstances — and so is taking down a drone in flight.
“The consensus is, no one has cracked the code on countering drones,” Mr. Holland Michel said. “It’s an unresolved challenge.”
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