A $1 million reward has been announced for information about the 44-year-old unsolved murder of Haroula Kipouridou, a 25-year-old singer found dead in a housing tower lift in Melbourne.

Ms Kipouridou was last seen alive in the early hours of July 3, 1981, after finishing a shift at a Fitzroy hotel where she worked as a singer. Two associates drove the Richmond woman home to a housing tower on Elizabeth Street, dropping her at the front of the building about 2am. They reported they did not notice anything suspicious at the time.

About half an hour later, Ms Kipouridou’s body was found on the floor of the tower’s lift. She had been severely physically and sexually assaulted.

Police interviewed a large number of people during the original investigation, and homicide detectives considered several people potential suspects. However, investigators have never been able to identify the offender or offenders, and no one has been charged over Ms Kipouridou’s death.

Victoria Police said the $1 million reward is being offered to help solve the murder, along with the possibility of indemnity from prosecution. The payment, for information leading to the arrest and conviction of those responsible, will be made at the discretion of the Chief Commissioner.

Homicide Squad Detective Inspector Dean Thomas said detectives remain determined to find who was responsible, even more than four decades later. “Haroula’s death was nothing short of brutal,” he said. “It involved a significant amount of violence and her last moments would have involved pain and fear.”

While news reports at the time suggested police had focused on one suspect, Victoria Police said there was not enough evidence to conclusively identify that person as responsible. Three months after Ms Kipouridou’s death, a $50,000 reward was announced, and authorities now hope the much larger reward will prompt someone to come forward.

“We know people who commit or are part of horrific crimes such as these will often disclose their actions to someone,” Det Insp Thomas said. “People’s circumstances can change over the years and someone who may not have wanted to provide information to police previously may now feel ready to do so.”

A coroner returned an open finding into Ms Kipouridou’s death in 1983.