Outrage over the lynching of a 13-year-old boy has mounted in Bangladesh as one of the suspects confessed after being arrested in Saudi Arabia.

Kamrul Islam fled to the Saudi city of Jeddah in the immediate aftermath of the attack but reports said he was arrested by the Saudi authorities after members of the large Bangladeshi expat community in Jeddah reported him to the police.

It's a brutal and heinous murder and we won't spare anyone

Akhter Hossain, police chief

In a video filmed by an expat TV station as he was led away to a waiting Saudi police car in handcuffs, Islam said that he had "made a mistake, please forgive me," before bursting into tears.

Samiul Alam Rajon was accused by his attackers of stealing a bicycle in the northeastern city of Sylhet although his family insist that the youngster was innocent.

Bangladeshi police have arrested five people over the July 8 killing of Samiul, who was tied to a pole and then subjected to a sickening assault in which he pleaded for his life.

Local police chief Akhter Hossain said his officers had arrested three people overnight, including the wife of one of the suspects and two men who were at the scene.

Police were also hunting for "two others who directly took part" in the beating, Hossain told AFP news agency.

"It's a brutal and heinous murder and we won't spare anyone," Hossain added.

Mass demonstration

An autopsy on Samiul found 64 separate injuries had been inflicted on the teenager during the assault in which he could be seen begging for water.

In the video, the terrified youngster can be heard screaming in pain and repeating: "Please don't beat me like this, I will die."

Samiul's attackers can be heard on the footage trying to force him to confess his involvement in the theft.

At one stage he is told to walk away. But as he tries to get to his feet, one of the attackers shouts: "His bones are okay. Beat him some more."

It is not clear who filmed the video although police initially said they believed it was captured on smart phone by one of the attackers.

Demonstrators formed a human chain on Monday around Samiul's home in Sylhet and a new mass demonstration in the city centre has been called for Tuesday afternoon.

Similar protests have been staged in other major cities, including the capital Dhaka.

Source: Agencies