A man and his wife were arrested by highway police with 327kg of compressed marijuana in their possession in Nam Phong district of Khon Kaen province late on Tuesday night.
Pol Lt Col Anan Witsetsamit, an investigator of Highway Police Division 4, said police manning a checkpoint between kilometre markers 378-379 on the Mitraparp highway in tambon Sa-at of Nam Phong district about 11pm stopped a pickup truck for a search.
The found 327 blocks of compressed marijuana, or ganja, each weighing one kilogramme, in 11 fertiliser bags, and also seized two mobile phones.
The driver, Charit Burikhan, 37, and his wife Siriporn Paprom, 22, both from Muang district of Nakhon Phanom, were arrested.
Charit allegedly confessed to having been hired for 80,000 baht to deliver the marijuana from Tha Uthen district of Nakhon Phanom to a client in Wang Noy district of Ayutthaya province.
He said the drug was smuggled across the Mekong river from Laos. The marijuana was sold for 4,000 baht per kilogramme in the area along the Mekong river and would fetch 20,000 baht/kg in Ayutthaya province and 50,000-100,000 baht in the South.