Maryland officials say they have uncovered a plot to use a drone to sneak contraband into a maximum-security state prison. (Reuters)

The two men parked on a side street near the Maryland state prison with a car full of drugs, pornography and tobacco, authorities said. They planned to load the items onto a green-and-white drone and send them soaring past the barbed wire and armed guards — and into the hands of an inmate.

But before the plan took flight Saturday evening, law enforcement thwarted the delivery.

Now Thaddeus Shortz, 25, and Keith Brian Russell, 30, are charged with illegal possession of drugs with the intent to distribute and related charges in what officials say is the first time a drone has been used to try to smuggle contraband into any Maryland prison. An inmate inside the facility, the Western Correctional Institution in Cumberland, could also face charges, authorities said.

“You can’t make this stuff up,” said Stephen T. Moyer, secretary of the Maryland Department of Public Safety and Correctional Services.

The weekend arrests highlight the challenges law enforcement officials face as drones become more popular and improving technology makes them easier to fly and harder to detect. Authorities across the country have been dealing with safety issues that arise when drones fly too close to airplanes, privacy concerns about cameras that can be attached to the devices, even instances of drones whizzing near the White House.

Authorities say two men tried to use a drone to get contraband into a Maryland prison. (Courtesy of Maryland Department of Public Safety and Correctional Services)

But more and more, people also are using drones to sneak drugs, cellphones and other contraband into prisons, threatening the safety of both inmates and correctional employees.

“Traditionally our first area of defense was anybody coming over the fence, through the fence or under the fence,” said Kevin Murphy, executive director of the U.S. Deputy Wardens Association. “Now this throws a whole new element on security because these things are airborne.”

A recent drone drop at an Ohio prison sparked a brawl over the marijuana, cigarettes and heroin it left behind. In South Carolina, authorities found that such a device carrying marijuana, cellphones and tobacco had crashed into the bushes outside a correctional institution. And four people were arrested in Georgia for a similar effort in 2013.

Authorities overseas are seeing the same problem. Australian officials have even called for no-fly zones over prisons to prevent the high-tech smuggling technique.

Although authorities declined to offer many details about the Maryland investigation, they said Saturday’s arrests were weeks in the making. Intelligence from within the maximum-security prison suggested that a delivery would be making its way to the area, said Maryland State Police Superintendent William Pallozzi.

“Information shared inside the institution was then shared with law enforcement outside the institution,” Pallozzi said. “We were able to turn it into a case, which resulted in the arrest of two individuals so far.”

Authorities said Shortz and Russell were spotted about 8 p.m. in a car on Hazmat Drive, a side street that runs off of the highway leading to the prison. Police said they made their move, and along with the drone, found synthetic drugs, pornographic material, tobacco and a cellphone in the car.

Police also recovered a gun, but authorities say it’s unlikely the weapon was part of the intended delivery since the drone they found can carry only six to eight ounces of weight at a time.

Online court records did not list current attorneys for Shortz and Russell. Attempts to reach Shortz’s family for comment were unsuccessful, and a woman who identified herself as Russell’s mother declined to comment.

Officials did not disclose where they think the drone might have landed or how a pickup would have taken place. But they did say they found contraband inside one inmate’s cell after the foiled drop. The inmate, whom officials did not name, had not been charged as of Monday.

“These are criminal enterprises,” Moyer said. “There are thousands of dollars often behind these types of operations.”

Moyer and Pallozzi said they plan to work with Gov. Larry Hogan (R) and state lawmakers to develop legislation and funding aimed at protecting against future attempts to smuggle via drone. Outfitting prisons with drone detection devices could cost $350,000 to $400,000 per facility, Moyer said.

“Technology has enhanced our lives . . . but all too often these same devices are being used in a negative manner,” Pallozzi said. “Law enforcement struggles to keep up with this type of technology.”

There remain, of course, other ways to get illicit materials behind prison walls — slipping the contraband to an inmate during a visit, for example, or sending it in with a corrupt guard. But Daniel B. Vasquez, a former high-ranking corrections official in California who now runs Corrections Consulting and Investigative Services, said he thinks the use of drones could become a “major problem” for prisons — especially as the technology becomes cheaper and allows users to pilot the aircraft from farther away.

“Very innovative,” he said. “A drone, to me, makes a hell of a lot of sense.”

Drones are increasingly popular nationwide. The Consumer Electronics Association estimates that hobbyists will buy 700,000 this year. And the Federal Aviation Administration is working to finalize drone safety rules, although it is restricted from imposing new limits on recreational drone owners.

After a crashed drone was found outside a South Carolina correctional institution, authorities installed watch towers and thermal imaging cameras to fight the flights of contraband, said Stephanie Givens, a spokeswoman for the state’s department of corrections.

Although drones could potentially deliver tools that could help prisoners attempt to escape or harm inmates and corrections officers, another major concern is the smuggling of cellphones. One of the state’s corrections officers was shot several times outside his home after inmates ordered a hit on him via a smuggled cellphone, Givens said. He survived the shooting.

“Cellphones are a way for inmates to communicate with the outside world, continue criminal enterprises and break the law,” Givens said.

She said the drones also may embolden those considering smuggling goods into a prison. Corrections officers sometimes see contraband tossed over a fence. Goods may be hidden inside a football or soccer ball.

But “with drones it’s a little bit less risk because they don’t have to run to the fence and deliver it themselves,” Givens said. “Individuals can sit in the tree line and introduce it from the cover of the woods.”

As drones continue to pose a problem, prison administrators across the country will have to step up their security and intelligence efforts to thwart attempts similar to the one in Maryland, said Murphy, who is also the chief deputy director for Arkansas Community Corrections.

“But one of the things I’ve learned,” Murphy said, “is once we figure out how to eliminate one threat, there will be something new that we will have to address.”

An earlier version of this story incorrectly said that a South Carolina corrections officer was slain after an inmate used a smuggled cell phone to order a hit. The corrections officer survived the shooting.