Mucchha, who resided in Nithari in a rented room, had been working as a gardener in the school for last one decade, Superintendent of Police (City) Yogesh Singh said.
Around a fortnight back, the school authorities had asked the gardener not to come to the institution due to his addiction to alcohol, he said.
Mucchha managed to enter the college campus last night and committed suicide by hanging himself inside the sports room, the police official said.
The body was spotted by the school staff this morning.
"Prima facie it appears to suicide but other aspects related to case are also being probed," he said.