European authorities continue to evaluate the risks posed by sinister "games" such as Blue Whale, Russian families say the risks are real and they want the world to know the price they have paid.Blue Whale is a teenage suicide challenge or "death group" that began in Russia several years ago. Within such groups, anonymous organisers encourage participants to kill themselves after the completion of a set number of tasks.
Civil society groups in Russia believe that at least 130 young people have taken their lives while playing Blue Whale, while reports of incidents and fatalities in places such as Ukraine, Estonia, Kenya, Brazil and Argentina have also surfaced in recent months.
The name Blue Whale may come from a song by Russian rock band Lumen called Burn. There is a "huge blue whale" that "can't break through the net", they sing. "Why scream / when no one hears / what we're talking about?" What is certain, safety campaigners say, is that thousands of young Russians have tried to play it.Sky News
met an amiable, first-year university student called Oleg Kapaev, who told us that he started playing Blue Whale because he was curious and bored.
He said: "I was sceptical about it, I couldn't believe anyone could actually kill themselves by playing it. Because I didn't believe it I guess, I decided to look for it."Oleg said it took several days of online investigation to find a Blue Whale group.
"There are a lot of groups on the internet but when I found the one called #(name withheld), I started playing for real. There was a link to their website, I registered and that was it. You just start waiting for the tasks."
An administrator gave him instructions like: "tell how me how you want to die" and "watch horror films all night". Later the tasks became more grotesque. The college student was told to cut patterns in his skin symbolising "the pathway to the end" and Oleg did exactly as he was told, posting a photo of his bloodied arm online as proof.
"They start psychologically manipulating you. It is very professionally done. You become a bit of a zombie."Typically, Blue Whale participants are given 50 tasks but Oleg was told that he was a better "player" than the others and that he would become "happier faster" when he completed task number nine: "jump from the top of a 20-storey building in Moscow".
Sleep deprived and disorientated, the 20-year old prepared to carry it out.
"I didn't feel like I needed to kill myself," he said. "I felt I needed to complete the task. I only had this thought in my head - that I need to complete the task."
It was the young man's parents who would ultimately save his life. When they discovered he had bought a plane ticket to Moscow - and saw a collection of suicide-obsessed comments on his social media page, they called the police. An officer managed to track him down and detain him before he jumped.
Oleg's mother Olga, told Sky News
that they were lucky.
"It's not a game, it's a game of death," she said.
"Some people will survive but other people will not. It is like gambling. That's it."
Sergey and Larisa Pestov were less fortunate. Last year, their 16-year-old daughter Diana died after falling from the roof of a block of flats in a city called Ryazan. Several weeks later, they found out that she - and a number of classmates - had been participating in an online "group of death".
Determined to do something about the phenomenon, the couple founded an online safety organisation which now claims more than 800 active volunteers. Together, they try to monitor online discussions groups and alert the authorities when they spot vulnerable teenagers online.
Still, it is not easy to help those who desperately need it, said a tearful Mr Pestov. "The parents will always blame themselves that maybe they did not give their children enough love or understanding.
"But it was impossible for us to understand what was happening at that time - to know the child was being pressured.
"They are made to hide everything from their parents."
The Russian authorities have made two arrests in connection with these online suicide challenges. A 21-year-old, who reportedly confessed to inciting 16 participants to kill themselves, was arrested last November while a 26-year-old Moscow-based postman was detained earlier this month. Both men are expected to face trial.
It is difficult to measure the real impact of Blue Whale in Russia. The country's teenage suicide rate has risen sharply to 720 in 2016 from 461 in the previous year but experts point to a range of factors, such as lack of opportunity, alcoholism and mental health issues by means of explanation.
Nonetheless, people like the Pestovs are convinced that internet-based suicide "games" have had a profound influence on that tragic statistic and they want the world to know about the dangers online.