Police have referred to the prosecution teens who sprayed graffiti on the walls of the historic Gyeongbok Palace in central Seoul last December, as well as a man in his 30s who allegedly convinced the teens to commit the crime.

The Seoul Metropolitan Police Agency said on Friday that the 30-year-old suspected mastermind, identified by his surname Kang, was referred to the prosecution for allegedly planning the graffiti stunt, as well as offering via Telegram to pay the teens to vandalize the palace walls.

An 18-year-old, identified by the surname Lim, and a 17-year-old, identified by the surname Kim, who spray-painted the walls, and a 19-year-old, surnamed Cho, who helped Kang run illegal websites, were also referred to the prosecution without a pretrial detention.

The police said that Kang, who has an extensive criminal record, is believed to have plotted the crime in an attempt to promote his websites, some of which contained indecent materials, to increase the price of advertisements on his sites.

Regarding the websites, Kang also faces charges of violating several laws, including those related to copyright, protection of minors against sex crimes, and information and communications networks.

He is also accused of preliminary plotting after inciting another minor to vandalize Sungnyemun, the Gyeongbok Palace walls and the statue of King Sejong the Great in Gwanghwamun. The 15-year-old reportedly backed out of the plan.