A teenager died after taking part in an online suicide game called the ‘Blue Whale Challenge,’ his family have said.

The body of Isaiah Gonzales, 15, from the Texan city of San Antonio, was found hanging in a cupboard with a mobile phone set up nearby to apparently broadcast his death.

The Blue Whale Challenge is an unsubstantiated phenomenon, whereby participants are said to be guided through a series of tasks over 50 days, such as self-harming and watching horror films all night, culminating in a suicide.

After examining his social media and internet activity, Isaiah’s family are convinced it was responsible for their son’s death.

“It talks about satanic stuff and stuff like that and my son was never into that,” his father Jorge told local broadcaster WOAI.

Isaiah’s death, along with that of an unnamed Georgia girl also thought to have been participating in the Blue Whale Challenge, would be the first in the US to be linked to the macabre game.

Deaths of teenagers have also been reported in Russia - where the game is thought to have originated - as a result of the challenge.

Mr Gonzales said the family had “no signs at all” Isaiah was planning on killing himself.

He is calling on other families to monitor their children’s internet activity.

Donald Trump says America is about to lose control of the internet

"I want them to go through their phones, look at their social media," Mr Gonzales said in a separate interview with KSAT-TV. “If they’re on that challenge already, they can catch that from happening.”

Police have not cited the Blue Whale Challenge as a factor in Isaiah’s death and its existence is yet to be confirmed in the US.

Some have claimed it is just a social media hoax. But some school boards took the possibility seriously enough to write to parents warning them of it.

Miami Police have also released a cautionary video which claims the challenge has “made its way into the US” and is “putting our kids in danger”.

The most controversial internet crazes Show all 7 1 /7 The most controversial internet crazes The most controversial internet crazes Gun Selfies Where it actually came from remains a mystery, but the 'Selfie' remains a popular feature on the internet - it was even named word of the year by Oxford Dictionaries in 2013. However, a number of gangs in America have taken it a step further, posting 'gun selfies' of themselves. Last year, two men were charged for 142 counts of possession of a firearm and were bailed by police after posting numerous photos. The craze has led to several calls for photos to be taken down, with parents fearing that children could try and create their own poses. Instagram The most controversial internet crazes Planking Originating in Australia in 2008, the trend of 'planking' swept Britain a year later. The craze, in which people form a straight figure with hands down by their sides, had thousands of participants uploading their efforts on to Facebook. While most were harmless enough, the more daring have been known to plank across railway tracks and between buildings, causing major health concerns. In 2011, a 20-year-old man died after 'planking' on a seven-story building in Australia. Twitter The most controversial internet crazes Twerking Twerking, a mixture of twisting and jerking, has been around since the late 1990s, but its popularity dramatically increased after Miley Cyrus 'twerked' at the 2013 MTV VMA awards with Robin Thicke, prompting fans to upload their own versions on Youtube - we've even had twerking stormtroopers. It's since been accused of corrupting the minds of young people and, last year, 33 students were suspended after making a video of themselves 'twerking' using school equipment. Machinima The most controversial internet crazes Happy Slap It's been almost a decade since the Happy Slap craze broke out in the UK, but what started out in as a small joke between friends in Lewisham in 2004 eventually became a nationwide phenomenon. Happy Slapping involved a victim being filmed on a camera phone getting slapped. As the craze spread, incidents became more and more vicious and it was linked to a rise in bullying in school playgrounds. In 2008, a teenage girl was sentenced to two years' detention after filming the fatal beating of a man. nydailynews.com The most controversial internet crazes Tombstoning 'Tombstoning' emerged in 2012 as a much more dangerous fad. It involved finding the highest rock to leap from, giving jumpers sufficient time to change their body position to resemble a tomb falling into the sea. It was invented initially as a way to keep cool during sizzling temperatures, but as the challenges became more daunting, some experienced horrific injuries as a result of jumping into shallow or rocky waters. Twitter The most controversial internet crazes McDiving While not as dangerous as other internet fascinations, McDonald's staff are now finding themselves on the receiving end of another internet craze. 'McDiving' started last year and normally comes at the end of an alcohol-fuelled night out, where it is then customary for a 'McDiver' to go to the nearest McDonald's and launch themselves over the counter. McDonald's franchises have even started hiring bouncers at peak times of the day to deal with any mischief makers. YouTube The most controversial internet crazes Gallon Smashing Given that glossy floors are prominent in supermarkets, it would be deemed acceptable to see the occasional person slip over. But this is no accident. Gallon smashing started to appear on Youtube last year and has becoming increasingly popular in the US. It sees agile teenagers throw gallons of milk in the air as well as hurtling themselves on to the ground. However, with the mess, cost and inconvenience that is caused, the 'gallon smashing' craze has seen security stepped up in supermarkets. YouTube

When the phrase #bluewhalechallenge is put into Instagram, users are directed to a content advisory warning and presented with a link to a suicide prevention website.

Two arrests have been made in Russia of men alleged to be behind the challenge. Ilya Sidorov, 26, was arrested last month.

Philipp Budeikin, arrested in May, told authorities his alleged victims were "biological waste" and he was "cleansing society".