Preliminary investigation into grenades found inside a parcel at a Bangkok courier service suggests it was an attempt to smuggle Army supplies for sale on the black market and an Army corporal has been detained, Colonel Winthai Suvaree said yesterday.

Meanwhile in the eastern seaboard province of Trat, which borders Cambodia, a large number of war weapons were discovered yesterday in a pickup truck that was involved in a road accident. The badly damaged vehicle carried a licence plate denoting that it belongs to the Army.

The pickup truck carried 30 AK-47 assault rifles, a number of M-79 grenade launchers, and more than 100 rounds of ammunition. The driver was a soldier from a military unit in Bangkok. He was in detention at a local Marines unit for investigation.

Winthai, the Army spokesman, said investigating officers had found the sender of the six M67 grenades, which were found in a package at a private courier service office in Bang Khen district on Friday while police investigations were continuing. He said the probe team had already identified the sender, a non-commissioned corporal, and he had been arrested and taken into military custody.

“Army chief General Chalermchai Sitthisart has ordered all military agencies to cooperate with the police to investigate this issue. He has also ordered close inspection of the weapons in the armoury,” Winthai said.

“If the military personnel were found to have been involved in any crime, they will be punished swiftly under both criminal and military laws,” he said.

He said that investigations so far have not shown links to previous bomb attacks in Bangkok, but it was believed that the corporal had smuggled the weapons from the armoury for sale, as the serial number on the grenades had been deleted.

Meanwhile, Bang Khen Police superintendent Pol Colonel Amnart Intharasuan said no charges had been filed against the suspect, as the officers have yet to conclude the investigation.

Since the suspect was a soldier, the case would be heard in the Military Court, he said. Amnart also said the suspect had not yet been transferred to police custody.

Meanwhile, Pol Maj-General Panuwat Lakboon, the Metropolitan Police Bureau deputy commander, summoned representatives from public transport operators BTS and MRT for a security meeting yesterday with police and military to inform them about tighter security procedures after a series of bomb attacks in Bangkok.

“The meeting is to let all partners work together on security surveillance and prepare to conduct drills for emergency situations in case any suspicious items were found in public areas such as on trains or in shopping malls,” Panuwat said.

“We want all people to keep monitoring for anything suspicious.”