Four Thai Muslims have been acquitted of belonging to extremist group Jemaah Islamiah (JI) and plotting bomb attacks against Western embassies in Thailand.
One of the accused was a doctor, Waemahadi Wae-dao
The high-profile case was dismissed after a Bangkok court found a lack of evidence against the men.
Their prosecution had stirred anger in southern Thailand, where a recent surge of violence has been blamed by the government on Muslim separatists.
Their lawyer, Somchai Neelaphaijit, vanished mysteriously in March 2004.
The case against them stemmed from the arrest in May 2003 of Singaporean Arifin bin Ali, allegedly a senior member of JI, which has been blamed for a string of bomb attacks in South East Asia, including the 2002 attack on Bali.
During the trial, Thai police told the court that Arifin implicated three of the four defendants as conspirators in plans to bomb the US, British, Israeli, Singaporean and Australian embassies in Thailand, as well as tourist sites.
Home to most of Thailand's 4% Muslim minority
Muslim rebels fought the government up to the mid-80s
Suspected militants have upped attacks this year, targeting Buddhists
Security forces' response criticised by rights groups
But the judges' verdict pointed to the prosecution's lack of physical evidence to back up its case.
"No evidence was found that they were setting up a JI network or gathering people to launch a terror attack," the verdict said.
The accused - doctor Waemahadi Wae-dao, school owner Maisuru Haji Abdulloh and his son Muyahid, and a manual labourer, Samarn Wae-kaji - all denied the charges, which could have seen them sentenced to 10 years if convicted.
The case against the men added to tensions in Thailand's troubled south, where more than 800 people have been killed in the last 18 months, in violence blamed on the heavy-handed authorities, and Muslim extremists.
Their lawyer, Somchai Neelaphaijit, a prominent Muslim lawyer and human rights activist, reportedly told colleagues he had received death threats after he agreed to take up their case.
The four men are to remain in detention while the prosecution decides whether to appeal.