The victim revealed the ordeal to her school counsellors and the police were tipped off by Childline activists.
Police arrested a sixth suspect from the Thoubal district on Friday. Five suspects, including a juvenile, were arrested earlier.
The FIRs narrate several alleged instances of sexual harassment like inappropriate touching, groping, stalking, and intimidation by Singh at different times and places over a decade.
Deputy Inspector General of Police Dalip Singh Kunwar himself visited the Vikasnagar area and took stock of the law and order situation.
As of now, a complete ban has been imposed on anyone entering or exiting the children's home until the investigation is underway.