Less than 30 hours after a video was released online showing three juveniles assaulting a boy with a concrete brick, Beijing police said on Monday that they have detained the alleged suspects.

According to the micro blog of the Beijing Public Security Bureau, the three suspects are juveniles, with the oldest born in 1997.

One of the suspects, who is surnamed Guo and is from Henan province, surrendered himself to police on Monday morning accompanied by his family. The other two suspects, who are both from Gansu province, were arrested in Hebei province, the public security bureau said.

The three juveniles confessed to assaulting the boy, whose name is Xiao Dong but whose age was not revealed, after a small dispute in Naixi village in the capital's Chaoyang district, authorities said.

An investigation is underway and Xiao Dong is receiving treatment in a local hospital.

Police refused to release details about the case.

The assault caught the police's attention after the video was spread online on Sunday morning. China Youth Daily first reported on the video via its micro blog at 10:23 am on Sunday in an aim to find out where the assault occurred and who was involved.

In the video, the three alleged suspects initially hit Xiao Dong with their elbows before they kick and slap him. Minutes later, his head is pounded with a large concrete brick, causing him to go unconscious. The attackers then urinate on the victim's face.

The video was forwarded 10,000 times in a short period of time on Sunday and generated more than 5,700 comments.

At noon on Sunday, the capital's public security bureau said on its micro blog that it had confirmed the site of the assault after netizens provided tips, and it asked police in Chaoyang district to look into the case.

Hours later, police officers in Chaoyang district visited the victim's home, found the owner of the video and began looking for the suspects, according to the bureau's latest micro blog post.

After the arrests were made, netizens began questioning whether the creator of the video was involved in the assault. The bureau did not address those concerns on its micro blog.

Xiao Chang, the photographer of the video, hangs out with the attackers and posted a message saying "going to turn myself in tomorrow" on his QQ, an online social networking tool, Legal Evening News reported on Monday.

He has been detained by police, the report said.

Yang Songbo, a micro-blogger, commented that the three suspects should receive heavy punishment for their alleged attack.

Another micro-blogger named William Wuzhi said the attackers should be given guidance and counseling.

"After all, the attackers are minors and what we want is to ask them not to assault others again. The serious punishment may not be effective," he wrote.

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