Image source, Getty Images

A 13-year-old girl has been safely returned home after she was allegedly kidnapped by a man she met through the children's gaming app Roblox.

Police said they arrested Howard Graham after discovering he had convinced the young girl to leave her home in Kansas - after just two days of speaking on the app.

The 33-year-old has been charged with sex trafficking, kidnapping and rape.

Roblox allows players to game with friends or strangers.

With around 150 million monthly users, it is one of the most popular children's games in the world.

Mr Graham and the young girl first met on the app on 18 February, Police Cpt John Ivey said at a news conference.

Two days later, investigators said the teenager snuck out of her house in the city of Topeka and was allegedly picked up by Mr Graham who drove her to his home in Clayton County, Georgia - some 900 miles away.

Over the next few days, police said they believed she was sexually assaulted "many times".

Police said eventually the girl sent a message to her mother through Roblox, giving the address of a general store where she had been taken.

Officers tracked down and arrested Mr Graham at his job on 1 March.

"We're truly lucky we found this young girl and she was alive," Mr Ivey said.

Police said they were searching Mr Graham's belongings to determine if he had targeted other children.

Roblox's mission, according to its website, "is to bring the world together through play". But the company has faced criticism for the explicit content that sometimes appears on its app.

A BBC investigation published last month found users on Roblox created sexually explicit rooms called "condo games" that allowed for inappropriate activity between children and adults.

Roblox spokesman James Kay said he was "deeply saddened" to hear about the recent case and would co-operate with the investigation.

"We have stringent safety systems and a team of thousands of moderators who enforce a strict set of community standards on Roblox, including zero tolerance for sexual content of any kind," Mr Kay said, noting parental controls and features that can limit children's contacts or turn off the chat function altogether.

"Safety on Roblox is at the core of everything we do," he said.