Natthorn said a Cambodian man, Pisit Liang, 29, was found to have visited Thailand 231 times, Trat resident Jakkapong Krairiang, 37, had visited Cambodia 11 times, while Flight Sergeant Pakhin Detphong, 40, had no record of leaving the country via the Trat border checkpoint.

On Saturday, Pakhin, an Air Force officer attached to the Internal Security Operations Command in Bangkok, was arrested along with Pisit and Jakkapong on charges of possessing weapons of war. Pisit Liang, 29, drove the other white Toyota Land Cruiser with Cambodian licence plates found at the scene where Pakhin’s truck ran off the road. Officials who came to his rescue found his truck to be carrying weapons and ammunition including 29 AK-47 rifles, 4,147 AK-47 bullets and 53 M-79 grenades. Pakhin on Monday confessed to buying the weapons from Cambodia for ethnic Karen “customers” in Tak province.

Meanwhile, deputy police spokesman Pol Colonel Krissana Pattanacharoen said a police probe found that Pisit’s car wasn’t linked to a high-ranking officer in Cambodia as some news reports had suggested.

Commenting on a separate case of the alleged involvement of military personnel in online weapon sales, exposed by the last week’s discovery of grenades in an unclaimed parcel at Kerry Express, a courier delivery service shop in Bangkok, he said no more arrests had been made in that case. Corporal Isarapong Phrombutr, whose name was listed as the sender of the parcel, remains in military custody.

It was reported earlier that Isarapong was scheduled to be transferred to Bang Khen police by Friday.