It is understood a 27-year-old man was badly beaten up at Edinburgh bus station by a group after responding to an organised sting operation targeting suspected paedophiles.
The incident was recorded and broadcast live on Facebook by a vigilante group called the Wolf Pack Hunters and showed the man being backed into a corner before he was punched and left with facial injuries which needed medical treatment at the Royal Infirmary.
Some horrified viewers phoned the police after witnessing the incident.
Four individuals - three men aged 17, 38, and 37 and a 47-year-old woman - have been arrested and charged with assault following the city centre incident.
The 27-year-old man was also arrested on an outstanding warrant.
Charlie Spudds was involved in paedophile hunting for two years and left due to concerns of how vigilante groups had changed their way of operating.
The 47-year-old, from London, said: “The man in this incident may have done things which I don’t agree with at all. But it does not give anyone the right to take the law into their own hands.
“Child sexual exploitation is disgusting and it needs to be stopped, but not like this. You can clearly see people hitting him on the video and he’s spitting blood and has a cut above the eye. It’s absolutely disgusting, who do they think they are?
“I was a huge fan of these groups but now they’re out of control which is why I walked away. “They need to hand information over to the police to deal with. I don’t agree with live streams or going to people’s homes. It’s now turned into a free for all with 158 groups across the UK and it’s ridiculous. Police need to shut down these groups before someone is killed.”
The video which was broadcast, and which has been obtained by the Evening News, shows the man being threatened with a woman saying a “wee visitor is coming to get you”.
One man punches him and then he receives multiple blows to the face and body which leaves him spitting blood.
Some viewers were horrified at what they were seeing.
One said: “This is too far.”
Another added: “It’s great what you do but you are potentially putting people at risk as well.”
A Police Scotland spokesman said: “Four people have been arrested and charged following an assault in Edinburgh city centre.
“The incident happened around 12.45pm on Thursday 27th August in Elder Street.
“A 27-year-old man sustained a number of facial injuries and was taken to the Edinburgh Royal Infirmary for treatment. He was subsequently arrested on an outstanding warrant.
“Three men aged 17, 38, and 37 and a 47-year-old woman have appeared at Edinburgh Sheriff Court in connection with the assault.”
Police Scotland has asked the public to contact them with information rather than take the law into their own hands and risking jeopardising ongoing investigations.
A spokesman added: “It’s understandable that people want to protect children from harm but we would ask them not to take the law into their own hands.
“Revealing the identity of suspected offenders can jeopardise on-going investigations and it can give suspects the opportunity to destroy evidence.
“It can also put children at risk by making it difficult to identify victims or potential victims. We would ask that if anyone has information about someone abusing a child online or off line then please contact the Police on 999 if you think there is immediate risk of harm, or 101.”
The warning came as An Edinburgh DJ has spoken of how his life has been ruined after being labelled as a paedophile by a vigilante group in a separate incident.
Colin Holt, 28, told the Evening News how his life has been hell since a group called Edinburgh Exposure posted he had committed a string of sexual offences against children.
He has been forced out of his own home, sacked from his job, received death threats and lost close friends as a result of the accusations.
Colin and 17-year-old fiancee were due to appear in court in September after being accused of engaging in sexual activity in front of two boys, aged 14 and 11, they were babysitting in July last year.
The case was dropped after the Procurator Fiscal decided there was not enough evidence to proceed.
Colin admits he has been in trouble with the law before and has been prosecuted for offences including assault and breach of the peace. However he maintains he has never been prosecuted for any offence of a sexual nature and claims his reputation has now been left in tatters.
He said: “My crime sheet is drunken stupidity, nothing against children or women whatsoever.
“I’ve had death threats, verbal abuse in the street, things thrown at me. It’s just been a nightmare.”
After naming Colin and his fiancee on Facebook the group organised a protest with more than 70 people gathering outside their Wardieburn Street East home. Police were called after the couple’s windows were smashed during a five-hour tirade with thieves later trashing the property.
The couple have been left homeless and are now residing at his fiancees’ mum’s home in South Queensferry with both searching for employment to be able to live.
He added: “We have had to start again from scratch because of this. They took everything and what they didn’t they had trashed. My partner was pregnant at the time and everything was in the house. We’ve had to buy it all again. We’ve been forced out of our own home. I’ve been sacked from my job.
“I loved my job and I was good at it. This page has come in and made me feel like I have no purpose.