They took away 10 grenades, seven M79 grenade launchers and more than 4,200 rounds of ammunition. The authorities also arrested Thirachai Udonwichian, 55, from Samut Prakan, at the house.

The raid on Thai Max Group in Pathum Thani’s Lam Lukka district was led by Deputy Police Commissioner-General Pol General Srivara Ransibrahmanakul and Provincial Police Bureau 1 deputy chief Pol Maj Sombat Milinthajinad at 8am.

Other items found in the raid included a quantity of methamphetamine, eight walkie-talkie radios, a power generator, sound equipment, a shotgun, 15 knives, four of them with handles made of protected animal horns; and a sword.

The ammunition was found in five crates, each containing 840 rounds.

Srivara said Thirachai, who was also running an electrical appliance repair shop, was first taken to the Kukot police station for questioning before being transferred to the Crime Suppression Division.

He said police also found pieces of red cloth printed with “Kot Tie Daeng Pathum FM 104.10 MHz”. Wutthipong once ran a community radio station in Pathum Thani, using that frequency.

Srivara said he would lead officials to check the suspect’s house in Samut Prakan to find out whether there were more weapons hidden there.

Thirachai reportedly testified that Wutthipong brought all the items to be left at the house and he had no idea that they were weapons.

A military source said the raid was carried out without a court warrant because the authorities invoked an earlier order issued under Article 44 of the interim charter. He said the authorities had learned that there were a lot of war weapons hidden in Pathum Thani and they suspect that more have been hidden near the house.

A police source said Wutthipong operated his community radio station from the house. But he fled after being accused of being behind violent attack on people protesting against the Yingluck Shinawatra government.

Meanwhile, First Army Area Commander Lt-General Apirat Kongsompong said the authorities would investigate whether the weapons and the suspect were linked to a group that has posted assassination threats against Prime Minister Prayut Chan-o-cha and Deputy Prime Minister Prawit Wongsuwan on Facebook.