The relatives of the deceased have alleged the hospital's negligence and also alleged that after her death the hospital was not handing over the body and demanding payment of around Rs 1.5 lakh.
The autorickshaw driver, identified as Laxmikant Savarkar and the child's kin took him to the hospital.
The incident happened on Thursday night when three people on a motorcycle were stopped by a group of four who demanded money from them for liquor, an official said.
The police have registered an offence of murder against her, following a complaint by relatives of the deceased.
The attack took place in Dipti Signal area under Kalamna police station late on Friday night, an official said.
The DCP said Sahni's modus operandi was to befriend women on websites, to invite them for a meeting in five-star hotels, and to rob them off their valuables.