Activists have called for the release of two ethnic Shan brothers arrested on suspicion of being involved in rebel attacks on a military facility and security checkpoints in northern Shan State earlier this month.

Khun Mai and Leng Sink, 28 and 24, are both teachers at a community school in Kunheng, southern Shan State. 

“We seek the immediate, unconditional release of two innocent Shan brothers arrested unlawfully,” the Tai Youth Network, a local community group, said in a statement Monday.

The group accused the military of breaching the constitution by holding one of the brothers for more than 24 hours without a court order.

Khun Mai, who was caught before his younger brother, was held for three days after his arrest before being brought before the court, the group said.

They also raised concerns over the possible use of “coercive” methods to force the men to confess.

The brothers were detained by the military’s security affairs unit at their family home about six miles south of Pyin Oo Lwin on August 17 and 19.

They are accused of aiding a coalition of rebels who attacked the Defense Services Technological Academy near Pyin Oo Lwin and ambushed local security checkpoints on August 15. During the attacks, the rebels also bombed a bridge on the major trade route linking Mandalay with Muse, a border trade town with China. 

The attackes killed three police officers and nine soldiers, and subsequent clashes on the route affected the trade with neighbouring China seriously.

Three ethnic armed groups – the Myanmar National Democratic Alliance Army, the Ta’ang National Liberation Army, and the Arakan Army – joined forces for the raids, which were seen as unusually bold.

The two brothers were brought to court on August 20 and remanded in custody. They are now detained at Pyin Oo Lwin Police Station, an officer there told Myanmar Now by phone.

Hpone Khaung, who founded Kawdai, the school where Khun Mai and Leng Sink teach, said the two brothers had been teaching Shan and English language classes at his school for a decade. They were on leave visiting home when they were detained, he said.

“They were wrongfully arrested,” he added. “There is no possibility of them having links with [the rebels].”

The men’s mother, Kham Mai, said they arrived home before the August 15 attacks, but the younger son left home again the same day, saying only that he had to travel somewhere.

On the night of August 17, authorities searched the house and seized a pair of walkie talkies, bedrolls with camouflage patterns, a laptop, a plant trimmer, and her sons’ passports, Kham Mai said.

The seized items belonged to the younger son, Leng Sink, she said, but authorities took away his older brother because Leng Sink was not at home.

The younger son immediately returned home after learning of his brother’s arrest and went to the police to hand himself in, Kham Mai added.

Hpone Khaung said Leng Sink’s walkie talkie was a low-frequency type easily available at markets in Shan State, adding that such devices are also used at his school. 

Police in Pyin Oo Lwin refused to disclose the charges likely to be brought against the two brothers since they are still under interrogation.

Myanmar Now was unable to reach military officials for comment. 

(Translation and additional reporting by Nyunt Win)