**Thai Prime Minister Abhisit Vejjajiva has met the Saudi charge d’affaires to discuss improving diplomatic ties, after a 20-year rift.**Relations soured after a Thai labourer stole jewels - including a rare blue diamond - from a Saudi palace in 1989.
Several months later, three Saudi diplomats were shot dead in the Thai capital Bangkok.
A Saudi businessman, Mohammad al-Ruwaili, believed to have witnessed one of the shootings, then disappeared.
Thai prosecutors are expected to rule on Tuesday whether or not to indict five former police officers in connection with the disappearance of Mr al-Ruwaili.
Job losses
Mr Abhisit told reporters: "We are trying to improve relations. On the legal cases, we are watching closely.
“The government will not interfere in the judicial process… I assured [the charge d’affaires] this process will be straightforward.”
The thief was caught in Thailand but when the Thai police returned what they thought were the real jewels - worth some $20m (£12.5m) - most turned out to be fake, causing further tension between the two countries.
Analysts say the dispute has cost billions of dollars in trade, and led to job losses for thousands of Thai migrant workers in Saudi Arabia.
Before the incident, as many as 300,000 Thais were employed in Saudi Arabia. The figure currently stands at just 15,000.
In 1994, the then Saudi charge d’affaires claimed the murdered Saudi diplomats had been “silenced”.
The Saudis are pressing for the case to be solved before the statute of limitations runs out next month. They also want the blue diamond to be returned before there can be any improvement in diplomatic relations.
The scarcity and value of blue diamonds is in part down to the fact so few places in the world mine for them.
The stones get their colour when the chemical boron is present during formation.