Authorities of the Government Children's Home at Ramavarmapuram in Thrissur had tried to register Raju for his Aadhaar card recently.
Uttar Pradesh welfare department's child helpline team reached the Balhedi village on Saturday after receiving information about the function.
The girl narrated the incident to her mother after which a police complaint was registered by family members, police said.
From now, teachers will be taught how to administer first aid during their training.
According to police, the mother, who hails from Bihar, has admitted to injuring the toddler to discipline him.
Arun, who will now be charged with murder apart from other cases, had tried to get the child out of the way several times before, the boy's relatives claimed.