Slender Man case: Girl who stabbed classmate when she was 12 sentenced to mental institution for 40 years

One of the two Wisconsin teenage girls who tried to kill a classmate to win favour with fictional horror character Slender Man has been sentenced to the maximum 40 years in a mental institution.

Morgan Geyser (15) had pleaded guilty last October to attempted first-degree intentional homicide in a deal with prosecutors to avoid a prison sentence.