Teen girl sentenced to 40 years in mental hospital for 'Slender Man' stabbing

A teen girl has been sentenced to 40 years in a mental institute for her involvement with a stabbing that was influenced by the fictional character ‘Slender Man’.

Morgan Geyser, 15, was sentenced to the maximum term by a Wisconsin judge in a case that started in 2014 after Geyser and her friend Anissa Weier, 16, stabbed another girl, Payton Leutner, 19 times.

Leutner survived the ordeal by running away from the woods, and she was later found by a cyclist on a road. The three girls were all 12.

Greyser and Weier said they carried out the attack to appease the Slender Man, a viral online boogeyman characterised as a faceless man with a tall and thin frame. He tends to be Photoshopped into old pictures and is sometimes associated with disappearing children or people going crazy.

Geyser made a deal with prosecutors last year, pleading guilty to attempted first-degree intentional homicide in exchange for prosecutors agreeing that she is not criminally liable due to mental illness. She was diagnosed with early-onset schizophrenia in 2014.

Prosecutors called for the maximum possible sentence, arguing that as recently as September, Geyser was still hearing voices and posed a threat to herself and society, according to AP. Brooke Lundbohm, a doctor called by prosecutors, said that Geyser was still dangerous.

Judge Michael Bohren said: ‘What we can’t forget is this was an attempted murder,’ the AP reported. He also reportedly described Geyser's sentence as ‘an issue of community protection.’

Weier also took a deal with prosecutors last year, pleading guilty to attempted second-degree homicide. In December, a judge sentenced her to 25 years in a mental hospital.