Police officers detain gambling participants Photo: Legal Daily

A routine flood-season patrol over the loess hills of Northwest China's Gansu Province took an unexpected turn when a police drone spotted a suspicious SUV parked at the entrance to a remote canyon. Within days, what began as a geological hazard inspection unfolded into a race against both crime and an approaching rainstorm.

Police in Lanzhou's Anning district recently dismantled an illegal gambling operation hidden in tents deep inside a mountain valley, detaining 18 gamblers and seizing 38,000 yuan ($5,300) in gambling funds. The operation also ensured everyone was evacuated from the area before heavy rainfall threatened flash floods and landslides, according to Legal Daily. 

The first clue emerged on the evening of July 5, when police used drones to inspect areas vulnerable to flooding and slope failures. During an aerial survey, officers noticed a black SUV with its license plate deliberately covered. Although the drone repeatedly broadcast warnings, the vehicle remained where it was.

Photo shows a black SUV with its license plate covered. Photo: media reports

After making their way through rugged terrain, officers found the SUV abandoned. A registration check quickly raised suspicions: its owner, surnamed Gao, had previously been investigated several times for organizing and participating in gambling. Further investigation revealed that Gao had recently purchased tents, generators, lighting equipment and a banknote-counting machine, while he and several associates with gambling records routinely disappeared after dusk

Police concluded that a makeshift casino was operating somewhere in the secluded valley.

As weather authorities warned of prolonged heavy rainfall that could trigger landslides in the loess mountains, police moved quickly. On the morning of July 9, drones guided officers to the site while ground teams closed in. Some gamblers were detained, but Gao escaped into the surrounding hills.

The pursuit soon took an unexpected turn. While searching the mountainside with a police dog, officers heard faint cries for help. Gao had slipped while fleeing and become trapped inside a mountain cave. Police rescued him before recovering the banknote-counting machine he had buried nearby.

Investigators later found that Gao had recruited five drivers to transport both gambling equipment and participants. He personally scouted remote valleys with poor mobile phone reception and difficult terrain before arranging for gamblers to be picked up at designated locations and driven to the temporary casino.

Gao and five other organizers have been placed under criminal compulsory measures on suspicion of operating an illegal gambling business, while the remaining gamblers received administrative penalties. The operation not only shut down a hidden gambling ring but also removed more than a dozen from a mountain valley just before dangers arrived.