South Korean police are investigating 17 US soldiers and five other people who allegedly smuggled or used synthetic marijuana via military mail.
This follows raids in at least two US army bases in May, including Camp Humphreys, its largest overseas base.
A Filipino and a South Korean have been arrested, while prosecutors review the cases against all 22 suspects.
A tip from the US Army's enforcement arm had sparked a four-month investigation by Korean authorities.
It was one of the largest in recent years involving American soldiers, US media reported citing Cha Min-seok, a senior detective in South Korea.
Joint raids by South Korean police and the US Army's Criminal Investigation Division found 77g (2.7oz) of synthetic cannabis, more than 4kg of "mixed liquids" used for vaping and a total of $12,850 (£10,440) in cash at the 22 suspects' homes.
They are accused of smuggling synthetic marijuana - known by the street names K2 and Spice - into the country through the US military's postal service.
Seven of them, including five soldiers, are thought to have been involved in the sale of the drugs, 12 were users and three acted as middlemen. A soldier's spouse and another soldier's fiancée are also involved, the police told the BBC.
The 17 soldiers are currently stationed at Camp Humphreys, about 48km (30 miles) south of the capital Seoul, and at Camp Casey, an army outpost about 40km north of Seoul, according to the police.
They allegedly distributed the drugs on the bases while communicating via Snapchat.
United States Forces Korea said on Wednesday that it was aware of the investigation. No soldiers are currently in confinement or being detained in relation to it, it said in a statement.
Synthetic marijuana is made to mimic THC, the main psychoactive ingredient in marijuana.
While it has similar effects to cannabis, it is typically more potent and has been reported to produce adverse health effects, including acute psychotic episodes, paranoid delusions and severe agitation.
It is difficult to detect because it is often used in liquid form in legal e-cigarette devices, the police said.
In South Korea, those convicted of trafficking marijuana face from five years to life in prison. Drug possession carries a maximum sentence of five years in prison or a fine of about 50m won ($37,200; £30,300).
Latest Stories
-
Implementing ESG framework in Ghana’s energy sector for sustainability
30 mins -
CAFCC: Dreams FC exit competition after 3-0 defeat in Kumasi
30 mins -
The detrimental effects of political interference on Ghana’s electricity sustainability
34 mins -
Prof. Opoku-Agyemang’s appointment as running mate intimidates the NPP – Benjamin Quashie
40 mins -
Black Stars physical trainer dead
41 mins -
Bawumia to kick off nationwide campaign for Election 2024 tomorrow
43 mins -
GUTA charges ECG to provide ‘dumsor’ timetable for businesses to plan
44 mins -
Reason for training professional counsellors is to heal a hurting world – CCP president
3 hours -
Woman allegedly brings dead man to bank to take out a loan
3 hours -
It’s a good feeling to score against PSG because I’m a Marseille boy – Andre Ayew
4 hours -
Joe Lartey Sr: A voice that brought life to Ghana sports and beyond
4 hours -
Bawumia promises to tackle issue most dear to Ghanaians as he begins nationwide campaign
5 hours -
Indian couple donate $24m fortune to charity to adopt monkhood
5 hours -
Australians call for tougher laws on violence against women after killings
6 hours -
African Development Council establishes mission in Benin for Francophone countries
6 hours