
HRW also reminded the Army chief, General Anupong Paochinda, that his credibility was on the line because he had stated publicly in late March that the Army would bring justice to the imam's case.
"Imam Yapa's case is a test for the Thai Army on whether it can hold abusers in its ranks accountable," said Brad Adams, Asia director at Human Rights Watch.
"General Anupong has put his credibility on the line. Will he allow a cover-up, or will he ensure that murderers in the ranks will be brought to justice?"
HRW said the commanding officer of Narathiwat's Task Force 39 has refused to implicate abusive soldiers behind the killing of the Muslim religious leader who was beaten to death just metres from where one of this two detained sons were being detained.
Major Wich Phuthong, the then commander of TF 39 at the time of the killing, told a court on June 30 in a post-mortem inquest that did not know who tortured and killed Imam Yapa when he was detained from March 20-21.
"He testified that written records of those on duty were destroyed. He further stated he had the authority to grant permission for interrogation of detainees in the camp, but no one made a request to him to interrogate Imam Yapa," HRW said.
A forensic expert told the court on June 30 that Yapa's cause of death was blunt force trauma that cracked his ribs, front and back. Bruises and wounds were found all over hisbody, including his eyes, forehead and lips.
Yapa also had long abrasion marks on his back, indicating he may have been dragged on his ankles across a hard and rough surface.
HRW quoted Yapa's sone as saying: "Soldiers took my father away at about 8 p.m. on March 20. That was the first interrogation. I saw them take him behind the camp clinic - not far from where I was detained. I could hear everything that happened to my father. I heard punching and kicking noises. I heard my father scream in pain.
That went on for at least two hours. I was so angry that I could do nothing to help my father. When my father was taken back, I saw those soldiers kept kicking him very hard all the way. When my father fell down, they kicked him again and again. They were laughing. My father could barely walk when they forced him to get up on his feet."
HRW said the torture and killing of Imam Yapa highlights the broader problem of ill-treatment of Muslims in Army custody during operations against separatist insurgents in the south, HRW said.
"No soldier has ever been prosecuted for abducting, torturing, or extrajudicially killing Muslims in the south," said Adams. "Because the evidence is so strong, this should be an easy case for the Army to show it's serious about addressing impunity."
"Ongoing abuses by Thai security forces and the culture of impunity have created a fertile breeding ground for insurgents to recruit new members and justify their campaign of violence," said Adams.
"The Thai authorities have the responsibility to restore peace and stability in the south, but they must do so in accordance with human rights standards," he said.