(New York) - The Thai government should stop making arrests using the GT200 explosives detector in the southern border provinces, Human Rights Watch said today. The controversial device, which has been used to detain large numbers of alleged insurgents, does not accurately detect the presence of explosive substances, scientific studies have found.

On February 16, 2010, Prime Minister Abhisit Vejjajiva announced the results of a government-sponsored study of the GT200, which concluded that the device was only successful in discovering explosive substances in 20 percent of the sample cases. This is even lower than the 25 percent rate expected in a randomized test. The government responded by calling for a review of the GT200's use by government agencies and said it would stop ordering the devices, but did not bar its use. Despite the findings, the armed forces said they would continue using the device.

"The Thai government has concluded that the GT200 performs worse than a roll of the dice, yet the Thai security forces haven't agreed to stop using it," said Brad Adams, Asia director at Human Rights Watch. "The GT200 has been the basis for large numbers of wrongful arrests, followed by mistreatment, in the southern border provinces."

The United Kingdom has imposed a ban on the export of "magic wand" substance detectors, including the GT200 (produced by the Kent-based Global Technical Ltd.), to Iraq and Afghanistan since January 27, after a series of media stories that exposed the lack of scientific rigor of these devices. The UK Foreign Office has reportedly stated that its embassies will urgently warn governments worldwide that devices such as GT200 are "wholly ineffective" at detecting explosives.

Field research by Human Rights Watch and the Thailand-based Working Group on Justice for Peace found that soldiers in the southern border provinces, where there is a longstanding insurgency, have also used the GT200 to identify suspected insurgents. Soldiers have used the devices during security sweeps of ethnic Malay Muslim communities or at security checkpoints, contending that the movement of a rotating antenna on the devices can find traces of explosives or gunpowder on suspects' bodies. Civil rights lawyers in the network of the Muslim Attorney Council say that since 2007 about 10 percent of suspected insurgents have been arrested on the basis of a GT200 reading.

Officials at the Justice Ministry told Human Rights Watch that GT200 readings cannot be used as evidence in court. However, Thai military forces consider GT200 readings a valid basis for exercising arrest and detention powers under the 2005 Executive Decree on Government Administration in Emergency Situations (Emergency Decree).

The Emergency Decree allows the armed forces to detain insurgent suspects for an initial period of 30 days in informal places of detention without assurance of effective judicial oversight, immediate access to legal counsel and family members, or independent monitoring. Research by Human Rights Watch has found that the Emergency Decree has frequently facilitated torture and other ill-treatment, including ear-slapping, punching, kicking, beating with wooden and metal clubs, forced nudity, exposure to cold temperature, electric shock, strangulation, and suffocation with plastic bags.

"It is common during security sweeps in the south to see Muslim men lined up on the roadside with their shirts off while being screened by a GT200," Adams said. "Many of those implicated by the GT200 have been arrested and then tortured."

Many ethnic Malay Muslim families in Narathiwat's Rue Soh district told Human Rights Watch that soldiers from the army's 39th Task Force regularly used the GT200 to look for suspected insurgents in their community in 2007 and 2008. For example, on March 19, 2008, soldiers from this unit arrested Imam Yapa Kaseng, 56. Two days later, soldiers tortured and killed him while interrogating him in the 39th Task Force camp. After this killing came to light, the 39th Task Force was relocated out of the southern border province. But no one has been prosecuted for his torture and murder.

Continuing abuses and lack of accountability by Thai security forces in the southern border provinces provide a fertile ground for separatist insurgents to expand and radicalize, Human Rights Watch said. Although the separatist Patani Liberation Fighters (Pejuang Kemerdekaan Patani) have suffered serious setbacks from counterinsurgency operations, they still maintain a presence in more than 200 ethnic Malay Muslim villages. They use state-sponsored abuses and injustice to justify their campaign of violence and terror targeting the civilian population, both Buddhist Thais and ethnic Malay Muslims, resulting in more than 3,900 deaths since 2004.

"All arrests based on the use of the GT200 should be urgently reviewed," Adams said. "In cases where this was the only evidence for detention, compensation should be paid and an apology issued."