The BJP has distanced itself from the controversy.
Sengar been charged with raping the young woman in 2017, when she was a minor.
The woman's father died in judicial custody in April 2018.
Atul Sengar, the brother of BJP MLA Kuldeep Singh Sengar was arrested after the Lucknow Director General of Police issued the arrest warrant against him.
The team will go into all the aspects and probe the incident till the CBI takes over the probe, the officer said.
The development comes a day after senior politicians from different opposition parties demanded a free and fair probe into the accident of the Unnao rape survivor and her family.
Surendra Singh said that children should not be given undue freedom and asked parents not to give mobile phones to them.
District and Sessions Judge Dharmesh Sharma held that the objections of the complainant party read like an engrossing thrilling story but were based on mere surmises and conjectures.
The trial court had awarded him the maximum punishment of life term with a rider that the convict will remain in jail for "remainder of his natural biological life" and also imposed an exemplary fine of Rs 25 lakh on him to be paid within a month.
Demanding the case be handed over to Central Bureau of Investigation, the victim alleged that the administration has done little to ensure the security of women in the state.
An order from the department of personnel and training said the case is being handed over to the CBI to probe "abetment and conspiracies" into the accident.
The girl tried to immolate herself near the chief minister's residence in Lucknow on Sunday.
Ahsan Ullah Khan, the additional district and session judge of the MP-MLA court in Sonbhadra, also imposed a fine of Rs 10 lakh on Gond which would be used in the rape survivor's rehabilitation.
Attacking the Congress government, the BJP claimed there is no rule of law in Rajasthan and the incident has put a question mark on the law and order situation of the state.
The court will continue the examination of other witnesses on Monday.
"She is sick and on life support system needing medication to support her blood pressure'
The court also asked the Uttar Pradesh authorities to file a status report by Thursday on the accident of the Unnao rape case victim.
The Unnao police booked Sengar under various sections of the IPC and provisions of the POCSO Act, but said the CBI will take a decision about his arrest.
The FIR, in which 15-20 unnamed people were also mentioned, was registered at the Gurubuxganj police station in Rae Bareli.
The letter narrates the incidents of July 7-8 when some people allegedly associated with Sengar, the sitting BJP legislator, threatened the victim's family with dire consequences.
Special judge Dharmesh Sharma, who is conducting trial of the cases, shall record her testimony.
The woman deposed before District Judge Dharmesh Sharma during 'in-camera' proceedings held at the seminar hall of the the Jai Prakash Narayan Apex Trauma Centre, her lawyer said.
Sources said BJP working president J P Nadda called up Singh to inform him of the party's decision and asked him to make an announcement.
Satyapal Singh, MoS HRD, said allegations can also be proven wrong.
Asha Singh, the mother of the rape survivor, said she is contesting the polls to ensure justice for the victims of such a heinous crime.
The mother of the Unnao rape survivor who received grievous injuries in a road accident in Rae Bareli has termed the Sunday's incident a conspiracy to wipe out her family.
Slogans of 'Unnao ki beti ko insaaf do, beti bachao' were chanted by MPs in the well of the House.
'Indian consciousness was raped in Unnao and then in Kathua'
The CM said his government has not deviated from its zero-tolerance policy on crime.
The apex court will on Monday take a call on moving the woman and her lawyer to AIIMS in Delhi, it said.
UP accounted for 14.7 per cent of all registered crimes against women in 2019. The state also recorded the highest number of cases against Dalit women.
Santosh Gangwar said that a hue and cry should not be created if one or two such incidents rake up in a big country like India.
'The government is running a 'beti darao', not a 'beti bachao' drive'
Speaking at a Balika Suraksha Jaagruktaa Abhiyaan programme at a school in Barabanki on Wednesday, a student asked, "If the person against whom we are complaining comes to know about it, and if we have an accident, what will happen?"
The bench also directed the Uttar Pradesh government to pay Rs five lakh to the lawyer, who is in a critical condition.
She is being given oxygen through a tube inserted in the windpipe. Her condition is stable but not out of danger, he said.
From police refusing to name the accused when the complaint was first filed to seeing her father tortured and killed, from her uncle being ensnared in an unrelated case to suffering an accident, which had clear marks of a conspiracy, the going was tough for her.
'Let the courts decide who is guilty and what punishment they should get.'
M C Mary Kom, who is also a sitting Rajya Sabha MP, said the alarming increase in the number of rapes in the country has left her feeling "hurt and helpless" while star shuttler Saina Nehwal condemned the 'ghastly crimes'.
'India doesn't belong to these people, it's ours.' 'We need to wake up and save India right now.'