Police recovered the body of a 21-year-old girl from a luxurious flat in Dhaka's Gulshan area on Monday.
The deceased, Mosarat Jahan Munia of Comilla, was a second-year student at a college in the capital.
The law enforcers suspected that the girl, a leading businessman's girlfriend, committed suicide in the flat at Gulshan 1 where she started living alone from March.
Meanwhile, the elder sister of the deceased lodged a case accusing Bashundhara Group Managing Director (MD) Sayem Sobhan Anvir of abetment of the suicide.
Anvir is the son of Ahmed Akbar Sobhan, the group's chairman.
Nusrat Jahan filed the lawsuit under Section 306 of the Penal Code with Gulshan police station early Tuesday, according to the case statement.
Md Abul Hasan, officer-in-charge of the police station, is investigating the case.
Police recovered the body on Sunday evening and later sent it to Dhaka Medical College morgue for autopsy, Dhaka Metropolitan Police Deputy Commissioner (Gulshan division) Sudip Kumar Chakraborty said.
The girl was a girlfriend of a businessman, he said without mentioning any name.
Police collected all electronic gadgets she used from the flat along with CCTV footages, he said.
The flat, where the businessman used to visit, was rented at Tk1 lakh and Tk11,000 was paid as service charge a month, but the young lady was an unemployed student, the police official said.
He said: "Munia informed her elder sister on Sunday that she was in trouble. Hearing this, Nusrat came to Dhaka from Comilla on Monday and rushed to her sibling's flat in the evening.
"Nusrat knocked at the door but there was no response from inside. She also found her sister's phone not reachable from a while ago. She, however, let herself into the flat and found her sister hanging from a ceiling fan."
Nusrat informed the owner of the flat about the matter and then the police were called in, the deputy commissioner said.
He also said that the police were communicating with the authorities to impose a travel ban on the businessman so that he could not fly via a private jet.
Meanwhile, media reports said Anvir and Munia had a relationship for the last two years.
Anvir kept her at a flat in Banani for a year and she went to Comilla after an argument with him.
The girl, however, started to live in the Gulshan flat in March.
She had a dispute again with Anvir following sharing of a photo of an iftar party on social media recently.
