The baby had been left with the 21-year-old suspect who was a friend of the father of the child, while the parents went to work.
When the mother returned from work, she found her daughter bleeding and crying and took her to hospital where it was confirmed the child had been sexually assaulted.
The suspect, a friend and colleague of the girl’s father in a private security company, also lived with the parents.
The parents informed the police and the man was arrested at the shared address.
The head of the district police, Chinmoy Biswal, said the 21-year-old suspect was thrashed by locals before police took him away, the Hindustan Times reports.
“The accused has said he did not run away after the crime as he regretted his mistake. We don’t know if he is saying the truth,” he added.
Speaking to reporters the child’s father said he had helped the suspect gain a job as a guard for a coffee shop.
“He belongs to my village and had been staying at my house for the last two months,” he said. “Since his duty was at nights, he would take care of my children when my wife and I would be away at work in the daytime.”
The couple’s two other children were at school.
The baby is being monitored in hospital and doctors said she suffered “cuts and bruises”, and did not have any injury that required surgery.
The child’s mother has also alleged that another man was involved with the assault, but police have made no further arrests.