The search for a man who raped a widow in her 80s twice in her Melbourne home more than 40 years ago has narrowed, police say.

Detectives from the sexual crime squad this morning said DNA technology advances and tips received in recent years led them to believe the rapist lived near Jessie Grace Lauder’s home in Mason Street, Newport, when he sexually assaulted her twice in the 1980s.

Lauder died in 1993 without ever seeing justice but police, who’ve offered a reward of $500,000 for information, said they believed the crime could be solved and urged the public to help bring him to justice.

Detectives from the sexual crime squad this morning said DNA technology advances and tips received in recent years led them to believe the rapist lived near Jessie Grace Lauder’s home in Mason Street, Newport, when he sexually assaulted her twice in the 1980s.

“Though Jessie is sadly no longer alive, these brutal attacks have had enduring effects on her family,” Sexual Crime Squad Detective Inspector Mark Burnett said. 

“Jessie was a vulnerable older woman who should have been safe in her own home.

“On the other hand, this man has lived these last 40 years with relative freedom and no repercussions yet for what he did.”

Police said Lauder was sexually assaulted twice in her home – where she’d lived for 55 years — first in September 1981 and again in July 1983, when the attacker referenced the earlier assault and warned her not to go to police.

The 82-year-old, who was widowed in 1977, was in bed when a man forced entry about 10pm on September 22, 1981, and entered her bedroom armed with a knife.

Police said he sexually assaulted her in another room and looked through her purse for money before climbing over the back fence into a vacant lot on Oxford Street.

It’s believed the same man returned on July 6, 1983, forcing his way in through the front door, taking Lauder to the kitchen to check no one else was home and then back to the lounge room to sexually assault her.

“During the second incident the man made reference to the earlier offence and warned Jessie not to call police,” police said this morning.

“During the incidents the offender is believed to have worn gloves, a beanie, work boots and items over his face to conceal his identity.”

But police said DNA technology advances and information received after the reward was first offered in 2016 had helped them narrow their search.

They described the rapist as 20 to 30 years old at the time and 175 centimetres tall with a fair complexion, dark hair and Australian accent.

The man might have lived on Mason, Johnston or Oxford streets or the neighbouring Lucius and Cunningham lanes, they said, urging anyone who may have known him to come forward.

“It is as important as ever that the person responsible is brought to justice and I absolutely believe that with the right information, it can be solved. If someone has knowledge of this and has lived with it for over forty years, now is the time to come forward,” Burnett said.

“Historical investigations are unique in that updates to science, methodology and legislation allow us to progress a case in a way that may not have been possible at the time of the incident, so receiving information even over 40 years later can still make an enormous difference.”

Police said the award would be paid “at the discretion of the Chief Commissioner of Police for information leading to the apprehension and subsequent conviction of the person or persons responsible for the aggravated rape and rape”.