In a court ruling on Tuesday on what has been dubbed the "budu bomb" case, the legitimacy and transparency of the military's unusual role in the justice process has again been questioned.
The Criminal Court convicted nine young Muslim men of plotting to set off a car bomb in the capital, based mainly on confessions made during their detention in military camps.
Seven of the men testified earlier they were tortured into making false confessions.
They were among at least 50 men rounded up by joint police-military forces on Oct 10, 2016 in Bangkok's Ramkhamhaeng area.
They were all later released but 14 were rearrested and put on trial. Five were acquitted by the court ruling. They were all from the deep South, a region plagued with insurgency for years.
While the authorities cited intelligence reports of the car-bomb plot, the only piece of evidence they located was a box loaded with budu, a southern-style fish sauce, found in an apartment of one of the suspects.
During their detention in military camps, seven of them alleged they were punched, head-locked, doused or sprayed with water, or locked in cold rooms to force them into making confessions.
Such military interrogation is made possible by two orders issued by the National Council for Peace and Order (NCPO) -- No. 3/2015 and No. 13/2016 -- which allow soldiers to arrest and detain suspects in national security cases for up to seven days without granting them access to lawyers or any other legal rights guaranteed by the normal justice process.
Given the conditions of their detention, a lawyer representing the defendants said it was not possible for the seven men to produce other evidence of torture beyond their testimonies in court. The lawyer said those methods of torture did not leave physical marks on their bodies.
Authorities later claimed to have found evidence in the guise of traces of explosives found on the hand of one suspect a week after he was detained. The man suggested this could have been planted on him during the arrest.
The court, however, ruled out their torture claims, citing a lack of evidence. The ruling found the nine men guilty of being part of a secret society and conspiring together.
Each was sentenced to four years in jail. The man found with traces of explosive was sentenced to six years in prison.
During the last four years, there have been at least 18 known cases involving allegations of torture during detention at military camps. Sadly, these claims have never been seriously probed by an independent body.
What is more worrisome is that prosecutors submitted confessions made during military detention as evidence in court during the past two years. Like the budu bomb case, they have become a deciding factor in court rulings.
Similar to the latest case, observers believe many confessions were made because the suspects were tortured, threatened, persuaded or otherwise coerced, and were denied access to lawyers or legal aid.
The budu bomb case should stand as a reminder to prosecutors that they can no longer rely mainly on evidence produced during military detention for cases they are probing.
It should be their job to dig deeper and get more proof, otherwise they should give suspects the benefit of the doubt.
The NCPO should revoke the two orders that give soldiers the unusual role of investigating cases against civilians.
More importantly, with countless torture allegations and a prevailing culture of impunity, it is time for Thailand to get serious about this issue.
The National Legislative Assembly should endorse a bill on the prevention and suppression of torture and enforced disappearance that has already been approved by the cabinet.
At the same time, law enforcement officers should not pursue national security or politically-motivated cases against civilians based mainly on evidence provided by the military's interrogation, which is neither transparent nor accountable.