This is the shocking moment a suspected pervert 'bites' a vigilante paedophile hunter in a desperate effort to escape during a Facebook Live sting.
The man allegedly sank his teeth into a member of the group "Silent Justice" after they tackled him to the ground and detained him for attempting to "groom a child online".
Disturbing footage shows the suspect screaming and banging his own head against the pavement before appearing to bite the man's arm as he battled to get away.
Vigilantes confronted the unidentified middle-aged man in Tamworth, Staffs., on Friday night and accused him of sending explicit messages to one of their adult decoys - posing as a 15-year-old boy - on gay dating app Grindr.
They claimed he bombarded the fake teen with oral sex requests then invited him to his home so he could ply him with cider and sexually abuse him, the Daily Mail reported.
When challenged, the man insisted he did not know the boy was underage and claimed he was just out walking.
He was chased and taken down after trying to flee and it took three people to restrain him while police made their way to the scene.
The dramatic video - viewed more than 50,000 times online - shows the vigilantes running up behind the suspect as he walks down the street.
They tell him: "Citizen's arrest, mate. We're a paedophile hunting group."
He says "excuse me" and tries to walk away but they seize him by the arm.
The suspect manages to pull free and runs through a nearby driveway, pursued by the group.
As he is pinned to the tarmac, he shrieks and repeatedly shouts: "Get off me."
They allow him to sit up as one of the vigilantes reads out explicit messages he allegedly sent to them.
The man covers his ears then tries to get up but is held down.
Suddenly, he starts cracking the back of his head against the concrete as members of the group shout: 'Whoa, whoa, whoa. What are you doing?
One man places his arm under his head to protect him, while the suspect blasts: "Just get the f*** off me."
He goes limp and closes his eyes, then appears to quickly turn his head and bite the man's arm - making him cry out in pain.
A female member of the group shouts: "Do not bite him."
The camera shakes and the footage is interrupted as they struggle to subdue him.
The suspect complains he "can't breathe" as they turn him onto his stomach and one of the men puts him in an armlock.
Police arrive minutes later and take him into custody.
The vigilantes gave officers copies of the chat logs and paramedics treated the man who was allegedly bitten at the scene.
A member of the group later claimed they had used "reasonable force" and said they intended to press charges against the suspect for assault.
Staffordshire Police confirmed a 49-year-old man was arrested on suspicion of attempting to groom a child for sex and remains in custody.
A spokeswoman for the force said: "Officers were called to the location following reports of an altercation between the man and several members of the public.
"The 49-year-old man was arrested on suspicion of attempt sexual grooming of a child and taken into custody for questioning. No child was present.
"During the disturbance a member of the public sustained slight injuries.
"We are reminding people not to take matters into their own hands or do anything that could hinder or jeopardise this investigation following the man's arrest.
"Please show restraint when commenting on certain individuals or circumstances. This case is owned by specially trained investigators and speculation is not only highly dangerous but can be damaging to the investigation process.
"Acts of retaliation will not be tolerated and we will take swift and appropriate action to deal with any offenders accordingly."
Anyone with information is urged to contact Staffordshire Police on 101, quoting incident 889 of July 14.