Arifun Nesa Arifa was found bleeding from a head wound in the garage of her residence on Central Road and taken to Dhaka Medical College Hospital (DMCH), where doctors pronounced her dead at around 12pm.
CCTV footage showed the 27-year-old had entered her building with her ex-husband Robin Khan on Thursday morning.
“The security camera showed Arifa and Robin walking in apparently having a normal conversation," said Kalabagan police station OC Yasir Arafat.
Sometime later, Arifa left the building alone and came back again. Then Robin was seen doing the same, but sometime after he returned, he was seen hurriedly leaving.
Arifa graduated from Eden College last year and had been living for the past six months with her mother, who was out at the time, police said.
Arifa's brother, Bulbul Amin, said his sister had lodged a general diary with Kalabagan police after their four-year marriage was annulled in December 2016.
"Robin had been threatening her since she started talking about divorce," he said.
Dr Sohel Mahmud, of DMCH Forensics department, said Arifa had died from being stabbed by a sharp object under her right ear.
Police found a bloody knife in the garage which they suspected had been used in the murder.