Unnao rape case: A teenage girl had accused BJP legislator Kuldeep Sengar of rape.

The probe into the truck-car collision that left the Unnao rape survivor critically injured and two of her aunts dead was handed over to the Central Bureau of Investigation or CBI by the centre on Tuesday, even as the opposition stepped up its attack on the ruling BJP.

An order from the Department of Personnel and Training, accessed by PTI, said the case is being handed over to the agency to probe "abetment and conspiracies" in the accident.

Earlier in the day, the BJP faced flak from the Congress, the Samajwadi Party and the Bahujan Samaj Party (BSP) as they accused it of giving political protection to legislator Kuldeep Singh Sengar, who was arrested last year for allegedly raping the woman when she was a minor in 2017.

In Parliament, there were walkouts and members walked into the Well of the House.

Sengar, already in jail, and nine others were booked for murder on Monday, a day after a speeding truck hit the car in which the Unnao rape survivor was travelling in Rae Bareli.

A letter written to the Chief Justice of India by the rape survivor and two family members just days before the car crash, expressing a threat to their lives, has also surfaced.

"The CJI has asked the Secretary General to go through the letter written in Hindi for preparing a note of it for his perusal," a Supreme Court official told PTI.

Doctors at the KGMU Trauma Centre in Lucknow said the 19-year-old rape survivor is still on ventilator. On Tuesday night, her condition was described as "stable". The lawyer who was also injured in the crash was also on ventilator.

A National Commission for Women (NCW) team visited the teenager's mother at the hospital.

Her family members sat on a dharna outside the hospital, demanding parole to her uncle from jail for the last rites of his wife. Later a court also granted him short-term bail to attend the cremation on Wednesday.

Congress workers led by Leader of the Legislature Party Ajay Kumar Lallu too sat on dharna and then courted arrest, demanding the "expulsion" of the BJP legislator from the party.

Uttar Pradesh BJP president Swatantra Dev Singh, however, said the legislator was suspended from the party long back following the rape accusation, and his status remains the same.

The party, however, has not given the date when this suspension took place.

Priyanka Gandhi Vadra, who is in charge of eastern Uttar Pradesh for the Congress, tweeted, "Why do we give people like Kuldeep Sengar the strength and protection of political power and abandon their victims to battle for their lives alone?"

On Tuesday, the state government announced a special investigation team (SIT) to probe the car crash. It had earlier recommended an investigation by the Central Bureau of Investigation.

"The government has become criminal-friendly," senior party leader Akhilesh Pratap Singh charged, referring to the Yogi Adityanath-led BJP government.

"It should act impartially but it appears to be standing alongside the one who is committing one crime after the other. The government's role is not impartial," he said.

In a tweet, Bahujan Samaj Party (BSP) president Mayawati said, "The meeting of BJP MP Sakshi Maharaj with the rape-accused BJP MLA in jail proved that the raped accused are continuously getting the patronage of the ruling BJP."

"The Supreme Court needs to take cognisance of it," she said.

The Lok Sabha witnessed loud protests and sloganeering by opposition members over the incident. Members of the Congress, the Trinamool Congress (TMC), the BSP and the DMK walked out of the House. The TMC members walked out twice.

More than 30 members, mostly from the Congress, were in the Well for nearly 40 minutes and were heard shouting, "We want justice".

The rape survivor's mother had alleged that Sengar, a four-time legislator who represents Bangermau in the Uttar Pradesh Assembly, raped her teenage daughter at his residence in 2017.

Sengar was arrested on April 13 last year.