A traffic accident in Pattaya has developed into a major criminal investigation after police uncovered illegal firearms, explosives and suspected links to cross-border scam networks.
The case involves Sun Mingchen, a 31-year-old Chinese national whose overturned car in Chon Buri province led officers to a much wider probe into his weapons, finances, travel history and possible criminal connections.
The investigation began on the evening of May 8, when Na Jomtien police were called to a crash in Bang Lamung district. Mr Sun, who was driving, and a Taiwanese woman travelling with him were not seriously injured.
However, police became suspicious after finding a handgun inside the vehicle. The discovery led to Mr Sun’s detention and prompted investigators to look more closely into his background.
A follow-up search at his residence in tambon Huai Yai later uncovered what authorities described as a large weapons stockpile. According to reports, the cache included M16-style rifles, C4 explosives, ammunition, body armour and equipment linked to explosive devices.
Thai media also reported that some items appeared similar to booby-trap devices, while others resembled components used in suicide vests.
The scale of the discovery quickly raised security concerns and brought several agencies into the investigation.
Weapons Cache Raises Questions Over Organised Crime Links
During questioning, Mr Sun reportedly told police he was a firearms enthusiast who had bought the weapons online as part of a private collection.
He also claimed he had been suffering from depression and had intended to use the weapons to take his own life. Police, however, said they were not convinced by his explanation.
Pol Lt Gen Trairong Piwpan, spokesperson for the Royal Thai Police, said investigators were still working to determine why the weapons were being kept and whether they were connected to wider criminal activity.
The case attracted further public attention after unverified online claims alleged Mr Sun had used ChatGPT to seek advice about sabotage. Authorities later clarified that investigators had only found general searches related to firearms and weapons.
As the probe expanded, police began looking closely at Mr Sun’s identity, immigration records and activities in Thailand.
Authorities said he had entered the country several times since 2020, most recently on January 27 using a re-entry visa. He was also found to hold a pink identification card issued to non-Thai nationals living in Thailand.
Online speculation later claimed that he may have used another identity to obtain Thai citizenship.
The Department of Provincial Administration rejected that allegation, saying the Thai citizen named online was a separate person who had legally obtained Thai nationality years earlier.
Police also questioned Mr Sun’s former Thai wife after tracing addresses connected to his registration documents.
Investigators said the pair married in 2021 before divorcing last year. His ex-wife reportedly told police that her name had been used in several legal and business registrations linked to Mr Sun’s rental car operations and other ventures.
Although police say there is currently no evidence that Mr Sun planned attacks in Thailand, investigators believe the weapons may be connected to organised crime across the border.
Cybercrime officers examining his financial records reportedly found transactions worth tens of millions of baht linked to bank accounts and cryptocurrency wallets allegedly tied to scam networks operating in Cambodia.
Authorities also discovered chat records, weapons-training images and other material suggesting Mr Sun had been gathering weapons since late last year.
Investigators believe the arsenal may have been intended for use by rival scam groups or for protection within criminal networks operating near the border.
Thai military affairs journalist Wassana Nanuam, citing unnamed security sources, claimed Mr Sun was a senior figure within such networks and had used Thailand as a safe base.
Responding to the claim, National Intelligence Agency chief Thanat Suwannanon said authorities had identified links between Mr Sun and scam operations but could not confirm whether he held a leadership position.
Illegal Firearms Transfers Come Under Police Scrutiny
The investigation has also raised serious questions about how restricted firearms ended up in civilian hands.
Metropolitan Police Bureau chief Pol Lt Gen Sayam Boonsom said several handguns seized from Mr Sun were originally police welfare firearms issued to officers under special procurement schemes.
Under Thai regulations, those weapons are not allowed to be sold freely and can only be transferred to heirs.
Police believe some of the guns changed hands several times before reaching Mr Sun, with at least one transfer reportedly dating back to 2011.
The findings have triggered further investigations into current and former officers suspected of involvement in illegal firearm transfers.
After his arrest, Mr Sun was held at a police station in Pattaya, where authorities said he refused food for several days and appeared to be under severe stress.
He was transferred to Pattaya Remand Prison on May 11 but was later taken to hospital after reportedly suffering seizures.
The Department of Corrections said medical staff found signs of an overdose involving personal medication. He was treated in intensive care before his condition later stabilised.
Officials said he remains under close watch to prevent further attempts to harm himself.
Police have also charged at least five Thai suspects in connection with the suspected weapons network. They include current and former military personnel, a shooting-range trainer and a person accused of supplying bank accounts used in arms transactions.
All suspects have denied the allegations and were released pending further investigation.
Authorities are continuing to examine companies connected to Mr Sun, his financial activities and possible links to organised crime.
For now, police say the case points more strongly to organised crime than terrorism. However, the discovery of explosives, military-style weapons and alleged links to Cambodian scam networks has kept the investigation firmly in the public spotlight.
