A 15-year-old boy was allegedly tortured in Kaliganj upazila of Lalmonirhat after being accused of stealing a microphone from a mosque, police said.

A 31-second video of the assault has gone viral on social media, triggering widespread outrage in the district.

Kaliganj Police Station Officer-in-Charge (OC) Abu Siddique said police began searching for the victim as soon as they saw the video and contacted his family.

The boy's mother filed a case with Kaliganj Police Station last night, naming three people and accusing 20 to 25 unidentified others on charge of torturing her son.

The victim is currently undergoing treatment at Kaliganj Upazila Health Complex.

Quoting local sources the OC said, the boy's mother had come to her parents' house in Kaliganj with her two sons around 10 to 12 days ago. On Thursday noon, the boy was passing a mosque at Chaparhat Bazar in Chandrapur union when several people stopped him and took him inside, accusing him of stealing the mosque's microphone.

When he denied the allegation, he was tied to a bamboo post with a rope and beaten. The video shows him with both hands bound as several people struck him with sticks, slapped and kicked him. At one point he collapses on the ground, his cries and pleas for help audible throughout.

Local resident Moslem Uddin said the microphone had gone missing from the mosque several days earlier, and suspicion fell on the boy after he was seen passing by on Thursday. Some people intervened and asked the attackers to stop, but they were ignored.

"The boy was crying, saying he did not steal the microphone and was not a thief, and that his maternal grandfather lived nearby. It was extremely inhuman," Moslem said.

The boy said he was on his way to the market when three people stopped him, asked his name, then slapped him and dragged him inside the mosque, where they tied him up and beat him severely.

Kaliganj Upazila Nirbahi Officer (UNO) Saiful Islam said he was deeply saddened after seeing the video on Facebook and had instructed police to investigate and take legal action.

He added that the boy's treatment was being monitored and that police had been told to arrest everyone involved.

"Operations are underway to arrest those involved," the OC said.