The incident took place in the second week of September when the girl, Alina, was allegedly beaten by the accused Rafique Shaill Shaikh, Inspector Narayan Patil of Waliv Police Station said.
However, an offence case was registered today.
The girl was also burnt with cigarette butts and admitted to a local hospital where the victim subsequently succumbed to her injuries, he said.
The girl used to live with her mother, who had been residing separately from her husband since the past seven months. The 26-year-old woman wanted divorce, but her husband was not agreeing for it, the officer said.
Prima facie, when the woman narrated his rejection to her paramour. In a fit of anger, he could then have committed the crime. However, the motive behind the incident is yet not clear, police said.
A case under Section 302 (murder) has been registered against the woman and Shaikh, but no arrest has been made, the officer added.