A Queens man is being monitored at Bellevue Hospital after confessing to murdering his 80-year-old mother with a crutch. Police found the crutch along with a bloody knife after receiving a call from Sergeui Mamontov, who uses the crutch because he only has one leg. Mamontov, who has a history of mental illness also tried to castrate himself, telling police he was "trying to remove the evil." Lyudmila Mamontova lived in the same Far Rockaway building as Mamontov, who a neighbor describes as "a caring son." When police arrived, he told them, "I just killed my mother and I don't know why." Neighbors say that his condition had worsened recently and that he had begun "talking Bible talk." Momontov lost his leg in a freak accident after being struck by a car and had a home attendant until three months ago when his workman's comp ran out.