BANGKOK -- After nearly five years of frustration, Saudi Arabia's royal family has reason to hope that it may finally get some justice in the case of more than $20 million worth of stolen jewelry -- thanks in part to a pistol-packing diplomat's rather undiplomatic behavior, the power of superstition and what might be called "the curse of the Saudi gems."

By all accounts, the case of the missing jewelry has become Thailand's worst scandal, leaving a trail of dead bodies, ruined careers and expensive ill will between the Saudi and Thai kingdoms. Certainly, superstitious Thais cannot be blamed for believing rumors, encouraged by the Saudis, that an ancient Bedouin curse hangs over the jewelry. Pilfered in Saudi Arabia by a Thai servant in 1989, recovered by Thai police in Bangkok and then stolen again, the treasure includes irreplaceable family heirlooms hundreds of years old.

At least 17 Thai police officers currently stand implicated in various aspects of the case, and private investigators hired by the Saudis have pointed to even higher-ranking government and other officials. Moreover, Thailand has lost billions of dollars in revenue from a Saudi ban on hiring Thai guest workers and a decline in Saudi tourism here.

Now, says Mohammed Said Khoja, the armed and outspoken charge d'affaires at the Saudi Arabian Embassy here, there is new hope of resolving the case and actually recovering some of the missing jewelry. Feeding this hope, he says, are the recent formation of a Thai police investigative team he can trust, a new amnesty program and the power of the "curse."

In recent weeks, more than 100 pieces of the missing jewelry have been turned in anonymously to police under a no-questions-asked policy. Among the first items returned were rings, earrings, a bracelet and three watches -- all made of gold and studded with diamonds. Accompanying the watches was a note that said they had brought bad luck. The latest and largest cache was surrendered in a northern Thai province a day after authorities dropped charges against three senior police generals, including two former national police chiefs.

According to Khoja, hundreds of items are still missing, including a "priceless" 50-carat blue diamond, a necklace of "very rare" green diamonds, more gem-encrusted watches and necklaces, "rubies the size of chicken eggs" and a $2 million bracelet containing, among other gems, a large blue sapphire. The sapphire was reset with some stolen pearls to make a necklace that, Khoja said in an interview, was seen adorning the wife of a senior police general at a party two years ago.

A dapper 60-year-old with a gray mustache, Khoja served at the Saudi Embassy in Washington in the 1960s and came to Bangkok as a career diplomat in March 1990 to follow up the case of the stolen jewelry. But as his frustration mounted, he publicly accused senior Thai police officials of lying to him about the affair, exposed a cover-up in the murder of a jeweler's wife and son and blamed a Thai police "mafia" for numerous threats against his life.

For that reason, he carries a Smith & Wesson .38-caliber revolver loaded with a nasty-looking bullet called, somewhat incongruously, the "Glaser Safety Slug." These bullets have a blue plastic tip containing steel pellets in a hard gel. The idea, a law enforcement expert said, is that they create a "shotgun-type wound" in the victim but won't go through and injure an innocent bystander. Hence the "safety" label.

In an interview in his heavily guarded office, Khoja shows no compunction about displaying this weapon, which he says he holds between his knees while riding to and from work in his limousine accompanied by a phalanx of bodyguards. He also proudly shows off the results of his frequent target practice: a paper cutout of a man with several holes in the head and chest. On his desk is a monitor that alternately displays scenes from security cameras.

While Khoja says he appreciates the work of the new police investigative unit, his persistent demands for the return of the jewelry and his continuing criticisms of senior politicians and police officials have sparked a feud with Thailand's new foreign minister, Thaksin Shinawatra.

"I don't like the way Charge d'Affaires Khoja has criticized Thailand," Thaksin snapped to reporters recently. "We have done our best. He has no right to demand. This is Thailand. This is not his country."

The chain of events that led to these circumstances began when Kriangkrai Techamong, a Thai servant, managed to disable an alarm system and steal nearly 200 pounds of jewelry from the palace of Prince Faisal bin Fahd in Riyadh, the Saudi capital. The prince, a son of King Fahd and a noted collector of antique jewelry, was away on a three-month vacation with his wife at the time.

After being alerted to the robbery, Thai police quickly caught Kriangkrai in January 1990 and "retrieved all the jewelry," Khoja said. The servant was later convicted and spent two years and seven months in jail. But immediately after his arrest, the case took a suspicious turn. For reasons that were never officially explained, the jewelry was taken to a Bangkok hotel for two days before being transferred to a police station, where the cache was laid out on a table and videotaped.

By the time the jewelry was returned to Saudi Arabia two months later, 80 percent of the items were missing, and most of the rest were fake, Khoja said. Valuable pieces were stolen before and after the display at the police station and wound up in the hands of high-ranking police, government and other officials, he said.

The Thai government acknowledges that police were involved in the theft, and several generals have been among those jailed or charged in connection with the case. All have denied wrongdoing, and no one has yet been officially accused of currently possessing the stolen jewelry.

Despite reports that some of the gems have been sold abroad, Khoja said he is sure the jewelry is still in Thailand and that most of it is held by "not more than 10 people."

Who they are is a secret that has cost the lives of several persons. Among them, Khoja asserts, are three Saudi diplomats who were gunned down in Bangkok on the same day in February 1990 and a well-connected Saudi businessman who disappeared shortly thereafter. The cases remain unsolved.

The businessman, Mohammed Ruwaily, was abducted by police and interrogated in a hotel room, then taken to a farm outside Bangkok where he was killed and his body burned, Khoja said he learned from private investigators. Two years after the disappearance, a police lieutenant colonel, Somkid Boonthanom, was officially charged with Ruwaily's murder, but the case was later dropped. In April of this year, Somkid was promoted to intelligence chief of the Bangkok police department.

The affair took another grisly turn in August when the 34-year-old wife and 14-year-old son of a prominent jeweler were found battered to death in a white Mercedes sedan, which had minor damage to its front end, on a dark section of highway north of Bangkok. Police initially declared that the deaths were caused by a traffic accident but were later forced to admit that the two were murdered. So far, 10 people, including three police generals, have been implicated in the abduction and murder, and an investigation is continuing.

The jeweler, Santi Srithanakan, a wealthy merchant with high-level police connections, is a key suspect in the case of the missing gems. He is accused of having received much of the stolen jewelry, apparently for the purpose of resetting or selling it. Authorities believe he can incriminate top police officials in the case and want to use him as a state witness.

Santi recently emerged from six months in hiding and told investigators he was kidnapped last year by police, who interrogated him at a ranch before releasing him in return for an $18,000 ransom. The investigators quoted him as saying he had been "repeatedly hunted" by a group of police officers and civilians who wanted to squeeze more information out of him on the whereabouts of the gems.

For Khoja, the case has meant dealing with six different Thai governments in the past five years and, until recently, making no headway. "I've lost five years of my life here, and it seems like 50," he said. Perhaps, he said, what little progress has been made so far may be attributed to his outspoken prodding, and to the curse.

"In some parts of the world, people don't believe in the curse, but it's true," he said. "Because if you take something from me by force, you create hate in my body, my heart, my soul. And this hate will follow you."