"He allegedly sexually assaulted the toddler. When the baby girl fell unconscious and started bleeding, he panicked and fled," a police officer said.
Gang-rape Dalit victim's death after ordeal in conservative state of Haryana sparks demand for crackdown as activists claim rape epidemic in India.
The incident happened in India's capital city of Delhi when the girls were playing outside their home.
Police have formed a special investigation team to catch the perpetrators as the incident is being likened to the 2012 Delhi gang-rape.
The girl was first raped by her neighbour and his friend. She was again raped by a passer-by, whose help she had sought to reach home.
The girl's mother said two days earlier, she had caught her husband doing something to the child.
According to the public prosecutor, this is the second most severe punishment under the POCSO Act in Tamil Nadu.
The August-born premature baby was adopted by a family from the western Indian state of Maharashtra.
The boy had allegedly inserted a twig inside the girl's private parts, which caused the girl to bleed.
The horrifying incident in the western Indian state of Maharashtra had sparked widespread outrage and protests.
The incident took place in Agra city in India's Madhya Pradesh state. Police suspect the victim's father is involved in the crime.
The girl, who is of the same age as the boy, told her mother that the boy used his finger and a sharpened pencil to assault her.
A vigilante mob doused a teacher in paraffin after they found him attempting to rape his 8-year-old student. Police intervened before he could be set alight.
The woman from Sirisedu in India, was enraged when her drunk husband began groping her in front of her children and severed his manhood.
The 41-year-old is the younger brother of the man who was earlier arrested and charged with raping the minor girl multiple times about seven months ago.
Delhi police say the woman may have backtracked out of fear.
The woman remained silent out of fear as the incident would damage the reputation of her family.
The complainant, who allegedly helped the accused in disposing the victim's body, has also been taken into custody.
The girl was allegedly raped by her father's colleague and is 30 weeks pregnant.
The girl's mother said her daughter was playing outside the house when the man tried to rape her.
The woman is said to be in a coma and battling for her life in a hospital.
Study finds disturbing evidence in the attitude of attackers towards victims in India's endemic rape crisis.