BANGKOK — Saudi Crown Prince Mohammed bin Salman received a rapturous welcome on a visit to Thailand this month, perhaps putting to bed one of the world’s odder diplomatic standoffs.
As the leader of a top global energy producer with billions of dollars in investments and purchases to offer, the Saudi crown prince ordinarily would be welcomed with open arms, but the prince visited only after Riyadh lifted three decades of sanctions.
The sanctions cost the Thai economy untold billions of dollars in lost trade, tourism and jobs — all because a Thai janitor, or perhaps a Thai gardener — stole a big diamond more than three decades ago.
The Blue Diamond Affair, with its toxic mix of greed, sleaze, betrayal and bloodshed, still reverberates. The rare 50-carat stone at the heart of the caper was never returned to Riyadh, and its current location is a mystery — or perhaps a secret.
During the crown prince’s Nov. 18-19 visit to Bangkok, he met and posed with world leaders at an Asia Pacific Economic Cooperation (APEC) summit, also attended by Vice President Kamala Harris and Chinese President Xi Jinping.
The prince, known popularly by his initials, MBS, was also one of the star attractions locally. He met with Thai Prime Minister Prayuth Chan-ocha and heard Thailand’s urgent appeal for Saudi tourists, natural gas and investments.
Niche export opportunities include Thai chicken and beef slaughtered according to Islam’s halal law. Saudi Arabia faces perennial labor shortages and may offer jobs to Thai factory, construction and shipyard workers, electricians and machine operators, petroleum and natural gas technicians, hotel and health personnel, cooks and housemaids.
The countries restored full diplomatic ties in January after more than three decades of hostility when Mr. Prayuth accepted an invitation to visit Riyadh. The crown prince’s reciprocal visit, Thai officials hope, can get both countries past the incident.
“The restoration of ties has mutual benefits for both countries,” the crown prince said during a Nov. 19 welcoming ceremony.
Thai politicians, businesses and media predict that Bangkok and Riyadh are leaping into a lucrative relationship that will help rescue Thailand’s troubled economy, but the Blue Diamond Affair first needs some tidying up.
It all began in 1989, when Kriangkrai Techamong, a Thai servant employed by the ruling Saudi family, made off with some 200 pounds of jewelry and other valuable gems from the palace of Prince Faisal bin Fahd. The haul, which was hidden for a time in a vacuum cleaner bag and spirited away to Thailand, included a rare 50-carat blue diamond, among the largest and most valuable of its kind in the world.
Saudi businessman Mohammed al-Ruwaili, who had close links with the Saudi royal family, vanished a year later in Bangkok while investigating the crimes. He is presumed dead.
Saudi Arabia, also angered by Bangkok’s inability to solve the apparent killings of four Saudi diplomats in Thailand around that time that may or may not have been related to the heist, expelled more than 200,000 Thai workers, banned Saudi tourist travel to Thailand, and reduced imports and exports.
Thai police captured Mr. Kriagnkrai soon after he sold hot gems to Thai jeweler Santhi Sithanakan for ridiculously low prices because the thief didn’t know their value. After just three years in prison, Mr. Kriangkrai was released in 1994.
An attempted rapprochement by the Thai government took a bizarre twist when police Lt. Gen. Chalor Kerdthes, who headed the investigation that caught Mr. Kriangkrai, flew to Saudi Arabia and returned some of the jewels. Saudi officials were angered to find that many of the gems were fake and the prize blue diamond wasn’t included at all.
In yet another twist, Gen. Chalor and other police officers were convicted of murdering the gem dealer and Mr. Santhi’s wife and child. The general was first sentenced to be put to death but was later given a 50-year sentence for his role in the crime. He was granted a royal pardon in 2015.
Riyadh-Bangkok relations withered as the diamond-linked chain of events unfolded. The number of Thais working in the Arab kingdom and sending home valuable remittances to their families went from as many as 200,000 at the time of the robbery to one-tenth of that by 2008.
More layers have been added to the mystery. A “confidential” February 2010 cable from the U.S. Embassy in Bangkok titled “The Curse of the Blue Diamond,” published by the anti-secrecy WikiLeaks website, reported that “soon after the incident, some wives of Thai elites, particularly police commissioners and generals, were photographed wearing jewelry strongly resembling the stolen Saudi jewels at various official or high-society events.”
“The Blue Diamond itself had been spotted several times on the wife of a police general in the 1990s,” the embassy said, but it later disappeared. That cable was sent to the CIA, the National Security Council, U.S. Pacific Command, and U.S. embassies in China, Saudi Arabia and elsewhere.
No evidence has proved definitively that Thai police received any of the missing jewels.
The U.S. Embassy cable said four of the officers convicted in the death of the gem salesman’s wife and teenage son confessed that “the police allegedly kidnapped the family members in order to pressure Santhi to reveal information about what happened to the jewels.” After the jeweler paid, the “police gang” killed his wife and child to cover their tracks.
In 2001, “two judges, one from the Appeals Court and one from the Supreme Court, attempted to extort” hundreds of thousands of dollars from Gen. Chalor, the cable said, apparently to declare him innocent.
The Supreme Court upheld Gen. Chalor’s death sentence for kidnapping and two murders, but he was released several years later.
Others in the gang were acquitted. One officer reportedly died in prison awaiting trial.
In January, a hopeful Mr. Prayuth met with the Saudi crown prince in Riyadh and said relations now “must be better than the last 32 years.”
“Both countries have agreed to fully restore diplomatic ties, including the appointment of ambassadors,” Mr. Prayuth said at the time.
A joint Saudi-Thai statement said Mr. Prayuth “expressed his sincere regrets for the tragic cases that took place in Thailand between 1989-1990.”
Thailand is committed “to providing appropriate security to members of the Royal Embassy of Saudi Arabia in Bangkok,” the statement said.
“We will move on and will not talk about the past anymore,” said Thai Foreign Minister Don Pramudwinai.