In July 2015, a North Korean native named Song Il Kim walked into a Honolulu hotel room to hand over $16,000 cash for three pairs of night vision goggles that he was planning to mail overseas.

Kim, 42, lives in China and was traveling on a Cambodian passport. He planned to ship the goggles from Hawaii to China in a box labeled “toys.”

The sale turned out to be a sting operation, and Homeland Security agents arrested Kim a short time later. Federal prosecutors charged him with violating the Arms Export Control Act, which regulates the sale of military equipment, and a judge sentenced him to 40 months in prison after he pled guilty in 2016. A separate smuggling charge was dropped as part of a plea deal.

But Kim’s crime wasn’t buying military-grade technology — it was his attempt to export the equipment without a license. Prosecutors argued that the high-tech military equipment could have ended up in the hands of the North Korean government.

The kind of gear Kim was trying to export was once prohibitively expensive, but low-end night vision gear is now marketed to hunters and can be purchased from sporting goods retailers for under $100. Advanced models can cost over $20,000, but are also perfectly legal and available to buy online. There are a variety of models on the market — goggles, handhelds, devices integrated in rifle scopes. Some models allow users to see in the dark by electronically enhancing the amount of light available, while others use thermal imaging to create a picture from the heat radiating from bodies or objects.

If Kim had an export license, very little would have prevented him from sending the equipment to North Korea, which is a major concern for experts who warn that military-grade night vision gear could fall into the hands of terrorists or rogue states.

Low-quality night vision equipment is easily available overseas and used by the militaries of most countries. But the high-end equipment available in the U.S. isn’t ― and if exported, that gear could give adversaries similar night vision capabilities to those of the American military, said Adam Routh, a research associate with the Defense Strategies and Assessments Program at the Center for a New American Security, a Washington, D.C.-based think tank.

While the Las Vegas massacre rekindled the debate over the millions of assault-style rifles owned by American civilians, there’s been much less public scrutiny of all the gear designed for military operations that is now marketed directly to civilians.

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A growing ‘hunting and defense’ market

Armasight, a San Francisco-based company specializing in night vision and thermal imaging equipment, sells the FLIR PVS-7 night vision goggles with an ad featuring a man dressed in a black military-style uniform. It offers many other kinds of goggles, binoculars and sights, including a set of $9,250 night vision goggles that, it says, have “optics that are equal to or better than current military night vision.”

Hunting retailer Cabela’s sells dozens of night vision scopes, including Armasight’s Zeus Pro, a $7,000 thermal scope. “Take versatile and sophisticated thermal visibility into your nighttime hunts,” says a blurb on the store’s website.

And a Texas company, HeliBacon, advertises expeditions where participants can hunt feral hogs under cover of darkness using night vision gear. Its website features pictures of customers swooping down on prey from helicopters, dressed in tactical gear and wielding machine guns ― something more like a military raid than a hunting trip. The tag line that appears when you visit the site is “Wait... so you’re telling us you’ve never shot machine guns from a helicopter?!”

Hunting with night vision equipment is illegal in many states. But in parts of Texas, shooting feral hogs is considered pest control, which means almost any type of equipment is allowed. For a rate of $695 per person, HeliBacon’s customers get the opportunity to use assault-style rifles and night vision gear similar to what U.S. special operations forces use — equipment that’s worth about $25,000 per set, according to HeliBacon co-owner Chris Britt.

“It’s exciting and our clients get a kick out of playing with all the latest cool equipment,” Britt said in an interview. “People are amazed at the crystal-clear images you get using the latest night vision.”

HeliBacon’s clients are given a safety course and shown how to use the night vision equipment before embarking on what are usually two-day outings. They are outfitted with semi-automatic rifles and sent into the field in cars without lights, so as not to scare their prey. They lure the feral hogs with corn. “We can get as close as 25 yards before shooting them,” Britt said.

Night vision equipment is a useful tool for civilians, advocates say. “When employed properly, night-vision equipment will open your eyes to the times usually dominated by four-legged critters and two-legged ne’er-do-wells, giving you the advantage,” claimed a May article in Shooting Illustrated, a publication of the National Rifle Association, on how to use the gear for “hunting and defense.”

When employed properly, night-vision equipment will open your eyes to the times usually dominated by four-legged critters and two-legged ne’er-do-wells, giving you the advantage. Steve Adelmann, Shooting Illustrated, May 2017

Several manufacturers of night vision equipment did not respond to phone calls and emails seeking comment about their products. A spokesperson for FLIR Systems, Inc., declined to comment. But the company acquired Armasight for $41 million last year — as much a sign of optimism for where that market is heading as any hog-slaughtering ad or company press release.

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A largely unregulated type of equipment

The federal Bureau of Alcohol, Tobacco, Firearms and Explosives does not regulate the sale or use of night vision equipment, a spokesperson said, and the legality of using night vision devices for hunting varies by state.

Ladd Everitt, the director of One Pulse for America, a gun violence prevention group, says that should change. Military-style gear like night vision equipment could be used in mass shootings like the one in Las Vegas, he said. (The Vegas shooter himself did not use night vision gear.)

Night vision equipment is “not the tool of sportsmen,” Everitt said. “It’s the tool of people who are seeking to kill as many people as possible in as short amount of time as possible.”

Others worry that illegally exported night vision equipment could end up in the hands of rogue governments or terrorist groups, and erode the upper hand the U.S. military has in night fighting.

“There is no practical use for the high-end night vision stuff for regular people,” Routh said. “If ISIS has these things, the concern is that our troops would be at a disadvantage because they are not as protected by the cover of darkness.”

The gear is already spreading to America’s enemies. The militant group that calls itself the Islamic State is reportedly using night vision gear in Syria, and last year, fighters allegedly linked to that group were arrested in Turkey carrying night vision equipment. The men were linked to an attack on Istanbul’s Ataturk airport that killed 45 people, according to Turkey’s state-run Dogan news agency. Night vision binoculars and military-style clothes were also found in the suspects’ suitcases, though authorities did not provide information about how that equipment might have been obtained.

If ISIS has these things, the concern is that our troops would be at a disadvantage because they are not as protected by the cover of darkness. Adam Routh, Center for a New American Security

Human rights groups say there are major concerns about where exported night vision equipment ends up. “We understand that nation states have the right to arm themselves,” said Adotei Akwei, managing director for government relations at Amnesty International USA. “But we are also concerned about shipments to countries where there are human rights abuses.”

Getting advanced night vision equipment out of the U.S. isn’t hard, experts say. Retailers generally include fine print stating that the equipment must not be exported without permission from the U.S. State Department or Department of Commerce. But no one checks to make sure those rules are actually followed.

In another recent case, a group of Ukrainians allegedly bought $190,000 worth of night vision gear online from retailers in the United States. The group had the equipment sent to post office boxes and arranged for an international delivery company to send it to Ukraine. They made “false statements to the freight forwarder about the contents of the packages, ostensibly so that the packages would be exported to Ukraine without the required licenses,” prosecutors charged in an arrest warrant for one of the men, Volodymyr Nedoviz, a Ukrainian citizen who lives in Queens, New York. Federal law enforcement agents arrested Nedoviz in March as part of an investigation into the sale of export-controlled night vision devices on the internet, one of seven major investigations into the illegal export of night vision equipment the Department of Justice undertook between 2014 and this year.

One of the devices Nedoviz bought, the Armasight Zeus-Pro 640, retails online for about $9,000 and is marketed as useful for “hunters, SWAT teams and military personnel.” A video on the Armasight website appears to show a soldier carrying a rifle as viewed through crosshairs.

Nedoviz “tried to circumvent laws that protect our national security by preventing specialized technologies from falling into the wrong hands,” U.S. Attorney Robert Capers said in a statement after the arrest. An attorney listed for Nedoviz did not return calls seeking comment. A spokesperson for the U.S. attorney said the case has not yet been scheduled for trial.

In Kim’s case, he didn’t even bother to try to hide his intent. He was caught after he posted an ad on a website seeking to buy advanced night vision equipment. Prosecutors said in court documents that they believe the gear would have ended up in North Korea, though they did not specify how they knew that.

While Kim’s transaction ran afoul of the law, not all exports of night vision gear are illegal. The Obama administration’s Department of Defense loosened restrictions on the export of military equipment, including some types of night vision equipment, in 2013, and put the Commerce Department in charge of regulating their export rather than State. The State Department oversees most military arms export sales.

The Obama administration defended the decision by saying that loosening restrictions on less sensitive items would free up resources to track more sensitive technologies that could fall into the wrong hands. “The easing of export licensing requirements for many items... is balanced by the increased oversight from Department of Commerce Export Enforcement Special Agents and analysts dedicated exclusively to export enforcement,” the White House said in a fact sheet.

Commerce tracks those exports much less carefully than State did, according to Colby Goodman, an expert on arms export regulations at the nonprofit Center for International Policy. Under Department of Commerce rules, companies can obtain licenses to export military equipment without oversight by federal authorities, he said. The Department of Commerce did not respond to requests for comment, but it said in 2013 that it would take steps to prevent equipment from falling into the wrong hands.

“When you lose government oversight, you lose the opportunity to ensure that equipment isn’t going to countries where U.S. intelligence thinks it should not be going,” Goodman said.