Teenager in âSlender Manâ Stabbing Is Ordered Released From Mental Hospital Anissa Weier does not pose a threat to herself or others, a judge said, ruling in a case involving an attack on a 12-year-old by 12-year-old friends. Anissa Weier being led into court for sentencing in 2017. She was sentenced to 25 years in the Winnebago Mental Health Institute. Credit...Michael Sears/Milwaukee Journal-Sentinel, via Associated Press July 1, 2021 A Wisconsin judge on Thursday ordered a 19-year-old woman released from a psychiatric hospital where she has been held for more than three years for her role in the nearly fatal stabbing of a friend, a crime she said was carried out to gain the favor of a sinister fictional character called Slender Man.