The bench of Chief Justice D B Bhosale and Justice Suneet Kumar, had asked a direct question to the advocate general.
The court had taken suo motu cognisance of the case on Wednesday. The case sparked further outrage after her father died on Monday of injuries reportedly sustained while in police custody. The judges also took strong objection to Advocate General Raghvendra Singh's submission that Sengar would not be arrested on mere registration of the FIR, saying, "The approach of the learned Advocate General is not only appalling but shocks the conscience of the Court in the backdrop of the instant case".
The court, completing the hearing, reserved its judgement for Friday at 1400 hours.
The court gave the direction to CBI after state government's counsel informed it that Sengar had been detained for interrogation and not arrested yet.
The court directed the central agency to carry out the investigation strictly in accordance with the law and consider filing an application for the cancellation of the bail granted to other accused in the Unnao rape case. It referred to the SIT report and said: "Medical officers and police officers, all were hand in glove with the accused to save them and you acted on this report against those officers but for arresting rape accused you need to do further investigation?"
Sengar, on Wednesday night, asked the Lucknow police to call him if there was an arrest warrant against him.
'As the case has been recommended to the CBI, hence there was no reason seen to initiate any action against the MLA.
The BJP MLA has been charged under the stringent POCSO Act and sections of the Indian Penal Code or IPC dealing with rape. "I have come here because TV channels were saying I will surrender", he appeared to taunt reporters, insisting that he was neither a fugitive nor a rapist.
Sengar was arrested by the CBI on Friday. On April 10, the police had arrested Atul Singh, brother of the MLA, in connection with the case.
An FIR was registered against Sengar in Makhi police station on Thursday.
In his letter addressed to the Chief Justice, Chaturvedi had demanded a court-monitored investigation into the case and also into the subsequent death of the survivor's father in judicial custody.
After the reports of supporters of Sengar clashing with mediapersons on Wednesday night, the Principal Secretary (Home) said that the government has made a decision to provide adequate security to the family of the victim and witnesses in the case.
The legislator welcomed the decision of the UP government to conduct a CBI probe and asserted that the findings of the central agency will aquit him from all "false" charges.
The victim welcomed the CBI probe in the rape case and murder of her father.