Police have arrested six people for attempting to steal oil from a public pipeline by digging an underground tunnel in the middle of an urban center in Cheonan, South Chungcheong Province.

According to Daejeon Metropolitan Police, the suspects, along with three accomplices, rented a two-story warehouse in Cheonan in February, from where they started digging the secret tunnel over the past four months.

The discovered tunnel, located 4 meters underground, measures about 75 centimeters wide and 90 centimeters high, stretching 16.8 meters. They were still 9 meters away from reaching the target pipeline when it was discovered.

The group disguised the warehouse as a logistics center and conducted the digging from inside a room they had made to look like cold storage. They also rented a gas station where they had planned to store and sell oil siphoned off from the pipe.

Among the suspects, a 55-year-old convict recently released from prison for a similar offense is alleged to have acted as the mastermind. Police investigators believe this person recruited the accomplices, including a technician to install the oil theft equipment, a site manager, a money handler and a tunnel digger.

The audacious scheme came to light following a tip-off to police.

A police official stated, "The crime scene was located directly beneath a four-lane road in a densely populated urban area, posing risks of ground subsidence and collapse; the tunnel has now been fully restored with the cooperation of relevant agencies."