Former co-chair of Green Party Korea Kim Ye-won has been under police investigation and was arrested for illegally possessing and using cannabis, police said Friday.

Police arrested Kim in February for allegedly using cannabis for entertainment purposes and keeping the product, which is strictly banned in Korea, at home since late 2022, it said. An investigation was launched in January, it added.

Kim offered to quit the progressive party after admitting that she was under a police probe for her alleged use of cannabis, according to a statement by the minority party Thursday. The Green Party Korea did not disclose when Kim notified the party that she had been booked by the police.

The Green Party Korea will "take action after consideration of the court ruling."

Kim, who had led the progressive party since July 2021, stepped down in February due to "private reasons," a party statement at the time said.

Law enforcement authorities have arrested a total of 12,387 people for alleged use of illegal drugs in 2022, up over 50 percent compared with four years before, according to police data presented to People Power Party Rep. Chung Woo-taik. The number of police officers dedicated to drug-related crimes came to 362 in 2022, up 29 percent over the cited period.

The Green Party Korea does not hold any seats in the 300-member National Assembly.