Police recovered the body, with the throat slit, on Tuesday from a room at the 'Neela Hotel' in capital's Abdullahpur.
The woman had checked in with the name 'Pushpa' along with a man, who registered himself as 'Durjoy' and a child around 10pm on Monday, police said quoting hotel authorities.
"She has been murdered sometime between 12am and 3am. No other injury marks other than on the throat were found," said Additional Deputy Commissioner Md Shahenshah.
He said false identities were used when they checked in adding they were looking for the man and the child.
The body has been sent to the Dhaka Medical College Hospital, said the senior police officer.