Bereaved families are calling on the online regulator Ofcom to shut down a "vile" website which promotes videos of the deaths of their loved ones.
The website, which we are not naming, has more than three million members and contains thousands of graphic photos and videos of real-life killings and suicides as well as executions carried out by extremists. Past members include those who have gone on to commit school shootings and murders, the BBC can reveal.
From Monday, Ofcom gets new powers to crack down on illegal content, but it may not be enough to close the site.
The site's admin team have said they would give their "full attention" to any Ofcom requests.
Under the Online Safety Act, the regulator can now take action over illegal content and that includes videos promoting terrorism or banned extremist groups.
All websites will now have to show they have systems in place to remove illegal material. If they fail to do so, the regulator can get court orders to block platforms or impose fines of up to £18m.
And from the summer all sites must have robust age verification systems to prevent children accessing a range of content.
But critics believe the legislation itself is weak and that Ofcom is not being robust enough in how it plans to police sites.
Mike Haines' brother David was murdered by members of the Islamic State (IS) group in Syria in 2014. The full uncensored video of his killing is on the site.
Mr Haines says the website is "vile" and describes the content on it as "horrifying". He points out there is no effective age verification and worries about the impact on children.
"It's like a drug," he says, "once you've had your first taste, you want another taste.
"So you want to see more, and it becomes more violent and more graphic and more disgusting".
David Haines' daughter, Bethany, says the comments on the videos are horrendous. "For years I have been trying to keep track and report sites such as this one. I have a fear that my son will one day see the video of his grandfather."
Mr Haines says the authorities must act now. "Every second that we delay in shutting this site down, we are endangering our youth."
Ofcom has spent the past 18 months since the Online Safety Act was passed drawing up the codes of practice that platforms have to follow.
The regulator can now start to exercise its powers to investigate and fine platforms for hosting illegal material.
Videos on the website are categorised into groups, which include executions by extremist groups as well as people being burned alive, decapitated by passing cars and crushed by trains.
Although violent and distressing, not all videos on the site would be deemed illegal.
Experts are concerned that viewing such content normalises extreme violence and helps in the radicalisation of young people.
BBC research into user names on the site has also identified a number of known online extremists, including two people who recently carried out school shootings in the US.
Last December, 15-year-old Natalie Rupnow killed two and injured six at her conservative Christian school, in Madison, Wisconsin.
And in January, 17-year-old Solomon Henderson opened fire in a school cafeteria in Antioch, Tennessee, killing one student and injuring another before turning the gun on himself.
Both were members of the website, which offers a "school shooting compilation" video.
In the UK, it's known that Nicholas Prosper, 19, who pleaded guilty to killing his mother and two siblings, was also a member of the site.
When he was arrested by police in September last year a shotgun and 30 cartridges were found nearby. It's thought he was planning to carry out an attack at his old primary school in Luton.
Prosper had an interest in mass shootings, including the 1999 Columbine High School massacre, one of the most infamous massacres in the US.
Dr Olivia Brown, who studies radicalisation and extremism at the University of Bath, says repeated viewing of these kinds of videos, especially school shootings, desensitises users.
"What might have seemed like an impossible solution to what someone might be feeling, would then become something that might feel like a viable option," she says.
The site is also deeply distressing for grieving families.
A video of base jumper Nathan Odinson has been put in the "falling" category of the website by site administrators.
The 33-year-old from Cambridgeshire was an experienced skydiver, but died when his parachute failed to open after jumping from a 29-storey tower in Pattaya, Thailand, last year.
A Thai friend was filming at the time and the video was posted first on local social media.
"Nathan was a family member that we loved," said his brother Ed Harrison.
"I found it amazing, literally, that people could be so half-witted as to share that video. I don't suppose these forum members have such thoughts in respect to their own family members."
Another video on the site shows Ian Price who died in hospital after he was attacked by two XL Bullies in September 2023.
From today Ofcom says platforms must have systems in place to remove illegal content.
"We won't hesitate to take enforcement action where necessary against platforms that fall short."
The challenge for Ofcom is that the death website is hosted in the US and its owner and administrators remain anonymous.
Ofcom told us "this content is deeply disturbing".
In a statement, the website's admin team said it "routinely receives reports from many government agencies and industry watchdogs".
It said any reports from Ofcom "will have our full attention".
https://www.bbc.com/news/articles/c3w1z248145o (Archive)
