Amid a firestorm of public outrage over the gruesome murder of 13-year-old Rajon, the Bangladeshi community in Saudi Arabia has helped police catch the man who was seen most active in beating the kid in a widely circulated video.

Saudi police detained Kamrul Islam in a suburb of Jeddah yesterday, two days after he left the country. He and some other brutes bludgeoned Rajon to death in Kumargaon Bus Stand area of Sylhet on the morning of July 8.

The boy died of brain haemorrhage; his body bore around 64 injury marks, according to an autopsy report.

The savage torture on Rajon sparked fury also among the Bangladeshi migrants in the kingdom, said Md Altaf Hossain, first secretary (labour) at Bangladesh Consulate in Jeddah. 

"Members of the Bangladeshi community here identified him [Kamrul] and contacted us. Then the Saudi police arrested him based on our information," he told The Daily Star over the phone yesterday evening.

Kamrul was staying at Al-Jamia'ah, where he was caught. Asked whether he would be repatriated, the first secretary said the man is supposed to face trial in the country where he committed the crime.

Working as a driver for years in Saudi Arabia, Kamrul came to his Sylhet home a month ago for Eid. He boarded a Biman flight on Friday from Sylhet Osmani International Airport for Jeddah, said an immigration officer on condition of anonymity.

In another development yesterday, Kamrul's wife Lipi Begum was arrested in Gobinganj area of Sylhet. His brother Muhit Alam, earlier arrested and prime accused in the murder case, was taken on a five-day remand following a Sylhet court order.

Police also detained another suspect, Ismail Hossain, 30, at Kamarkazi in Sylhet Sadar upazila, said Akhtar Hossain, officer-in-charge of Jalalabad Police Station.

The case was filed with Jalalabad Police Station accusing Muhit and Kamrul, their accomplice Ali Haider, 34, watchman Moyna Mia alias Boro Moyna, 45, and seven other unnamed people.

The sickening torture video shook the nation to its core and stirred outcries in the social networks and the mainstream media, with the 28-minute clip and still images going viral.

Kamrul, in a black T-shirt and lungi, was seen hitting the boy with stick in the feet, joints of legs and shoulders and in the head.

Tied to a pole, the boy screamed for help, cried for water and begged for his life. But the group showed no mercy. They laughed, joked and filmed their madness to share it in the social media.  

Bangladesh star cricketer Mushfiqur Rahim holds a placard protesting child abuse. Photo: Mushfiqur Rahim's Facebook page

They kept beating him, at times knocking him down to the ground, and asking how he would like to take the beating. "We know all methods of beating," one of them is heard saying.

When Rajon howled for water, they told him to drink his own sweat.

When Rajon wanted some water, they told him to drink from his own sweat.

After the killing, the culprits were taking his body on a microbus to dump it in a secluded place, but the locals found them and managed to catch only Muhit. The police recovered the kid's body from the microbus.

Lubna Akhtar, mother of the victim, said her son left home early in the morning to sell vegetables as his father Sheikh Azizur Rahman, a microbus driver, was out on a trip.

As Rajon did not return home all day, Lubna went to the police station that night to file a general diary. There, she was told about a boy's body recovered earlier in the day. To her horror, she found it was her little one.

Rajon, eldest of Lubna's two sons, studied up to class-IV. After dropping out, he started selling vegetables to support the family in Badeali village under Sylhet Sadar upazila.

OC Akhtar Hossain said the video of torture was not recorded in secret. "The criminals themselves recorded the heinous act and uploaded it online. They got sickly pleasure out of it all," he told The Daily Star.

"Rajon died of brain haemorrhage, and around 64 injury marks were found in his body," he said citing the autopsy report by Sylhet MAG Osmani Medical College and Hospital.

Tasmina Islam, a doctor who performed the autopsy, handed the report to the OC around 2:00pm yesterday.

On Sunday night, police formed a special team to find and arrest the culprits.

Headed by Sylhet Metropolitan Police's Additional Deputy Commissioner Rahmat Ullah, the four-member team has already started working.

"None will be spared. The culprits will be tried as per the country's existing law," State Minister for Home Asaduzzaman Khan Kamal told reporters at his office yesterday.