Chinese authorities have arrested 26 people who were part of an iPhone smuggling operation between Hong Kong and the mainland city of Shenzhen. The criminals used aerial drones to connect two 660-foot cables between two high-rise buildings, and then passed as many as 15,000 iPhones per night across the border.

According to Reuters, the state-owned Legal Daily reports that it was the latest escalation in smuggling operations that have been going on for years. “It’s the first case found in China that drones were being used in cross-border smuggling crimes,” customs officials said.

The arrests were made in February as part of a joint anti-smuggling effort between authorities in the two cities.

It’s unclear from the reports exactly which drones were used, but Drone Life speculates that at least one was a modified DJI Phantom 4, judging from the images released by Chinese media. Ironically, the drone may even have been manufactured in Shenzhen, which is a Chinese tech hub and home to a DJI plant.

Once the cable was attached between the buildings, the smugglers sent individual packages of 10 iPhones across. Working in the dead of night, they were able to pass as many as 15,000 phones per night across the border. Over a six-month period, that added up to 500 million yuan ($79.8 million) in refurbished iPhones.

Although the majority of iPhone manufacturing is done in China, taxes and fees make it prohibitively expensive to own one, and there’s a thriving black market for smugglers. An iPhone that costs $1,000 in the U.S. may run upwards of $3,000 in China. One woman was recently caught at the Chinese border with more than a hundred phones and 75 luxury watches strapped to her body. Other enterprising criminals have used Twinkie boxes, coffee tins, and toothpaste containers.

Drones have also been used to smuggle contraband into prisons. A gang in Britain used a quadcopter to deliver goods to inmates inside, and another drone laden with drugs dropped its payload into an Ohio prison yard, resulting in a near-riot among inmates.

Legal Daily reports that Chinese authorities will step up their efforts to combat drone smuggling by — you guessed it — using their own drones equipped with high-resolution cameras.