The CBI told the court that Sengar and his associate Shashi Singh conspired to commit the crime at Sengar's residence in June 2017 when the victim was a minor.
The CBI counsel said the agency has sufficient evidence to establish the victim’s allegations against the accused.
The victim told the CBI she was 17 when she was called to Sengar's house in Unnao on 4 June 2017. She said co-accused Shashi Singh met her at the gate and took her to the lawn. Sengar then arrived and dragged her into a room where she was gang-raped, a report in Indian daily Times of India said.
The case came to light when the victim attempted to set fire to herself outside the residence of Yogi Adityanath, the Chief Minister of Uttar Pradesh, in April last year. She took the drastic step after her father was jailed under the Arms Act on false charges after lodging complaints against Sengar and others.
The rape victim's father died in prison the same year, allegedly after being assaulted by the lawmaker’s brother and his aides.
Last month, the case made headlines again when the victim was critically injured in a road accident and had to be admitted to the trauma centre of a hospital in Lucknow.
A speeding truck hit the car in which she, her two aunts and a lawyer, were travelling to meet her jailed uncle.
After the accident, the truck driver fled but was eventually arrested. Sengar and nine others have been charged with murder.
The victim's counsel said both Sengar and Shashi Singh were in violation of Sections 161 and 164 of the Indian Penal Code (IPC).