NEW DELHI - A 19-year-old who accused a powerful legislator of rape is fighting for her life following a deadly car crash in a case that has led to an outpouring of support across India after she had warned of a threat to her life.

The woman, who cannot be named under Indian laws and was 17 at the time of the alleged rape, was travelling with her two aunts and lawyer from Unnao to Rae Bareli in the central state of Uttar Pradesh when their car was hit by a truck with blacked-out licence plates.

Her two relatives were killed in the accident on Sunday (July 28) while she and her lawyer Mahendra Singh remain in a critical condition.

The Central Bureau of Investigation (CBI) is investigating whether Kuldeep Singh Sengar, a member of the legislative assembly in Uttar Pradesh who has been in jail on the rape charge since last year, instigated the crash.

Mr Sengar was expelled from Prime Minister Narendra Modi's party on Thursday.

The case has shone a light on the struggle for rape victims to get justice in India.

The Supreme Court on Thursday ordered federal investigators to conclude a probe into the accident within two weeks and conclude the trial in the cases of rape, intimidation and murder within 45 days.

The court had taken note of a letter written by the victim and her family before the crash to Chief Justice of India Ranjan Gogoi, highlighting intimidation and threats from Mr Sengar.

The Supreme Court also ordered the transfer of the five cases related to rape and murders out of Uttar Pradesh, where the legislator remains an influential political figure, to Delhi and payment of Rs 2.5 million as interim compensation by the Uttar Pradesh government to the family.

Sexual crimes against children have emerged as a real area of concern for India which is struggling to provide a safe environment for women and girls.

According to the National Crime Records Bureau, child rape cases increased from 5,484 in 2009 to 13,766 in 2014.

In 2016, 19,765 cases of child rape were registered.

More than 80 per cent of the cases were perpetrated by family members or those known to the family.

Yet a key struggle for victims and their families remains to get justice with court cases taking years - a problem often exacerbated by low conviction rates and poor investigation.

In this case the ruling Bharatiya Janata Party has also been facing pressure for not taking any action against Mr Sengar while he has been behind bars.

Opposition parties accused the BJP of inaction and failure to protect the victim and her family - even as street protests have taken place seeking justice for the victim.

The BJP, in a sign of the building public pressure, expelled the legislator from the party, on Thursday.

Critics accused the party of doing too little too late.

"Whatever the government can do, it is has done too late," Mr Dinesh Sharma deputy chief minister of Uttar Pradesh, where the BJP is in power, told Indian media.

"We have tried to ensure justice for the Unnao teen."

Yet the Unnao case is seen to be an extreme example of how rape victims are harassed.

The case came to national attention after she threatened to set herself on fire outside Uttar Pradesh chief minister Yogi Adityanath's house because the police had refused to register a case against the four-time legislator in Uttar Pradesh, a state that is politically important for the ruling BJP.

Days before the victim's father was involved in a fight with Mr Sengar's brother Atul Singh. He was arrested by the police a day later on charges of illegal possession of firearms and died of his injuries while in police custody.

The Indian Express, in an editorial on July 30, said: "... the impression is grim and inescapable: Of a law enforcement machinery that systematically hounds the victim, a powerful accused who is able to spread fear even from inside jail. And a political regime that, at the very least, turns a blind eye to horrific injustice."

Activists said the case also underlines how India needs a system to protect victims once they come forward.

"The Unnao case brings in sharp focus the need for a robust victim protection system in India and accountability of functionaries within the criminal justice system," said Ms Swagata Raha, consultant - restorative justice and legal affairs at Enfold India, a non profit focusing on child sexual abuse among other issues.

"Threats, intimidation, and coercion are routinely faced by all victims of child sexual abuse. With negligible support from the criminal justice system, most victims are left to navigate these challenges on their own.

"Although the Indian Supreme Court has directed state governments to implement the witness protection scheme framed by the National Legal Services Authority, most states have not taken any concrete steps."