A WOMAN claims to know the man responsible for one of Victoria's most baffling crimes, the Easey Street murders in 1977.

Suzanne Armstrong, 28, and Susan Bartlett, 27, were stabbed to death in a frenzied attack in their home in Easey Street, Collingwood, on the night of January 10, 1977.

Homicide squad veteran Detective Senior Sergeant Ron Iddles says a woman called him on Tuesday to say she thinks she may know who committed the murders.

"She said 'listen I don't know whether I'm right but I've had this suspicion about a man who's now 82' and she told me a long, long story," Det Sen Sgt Iddles told Fairfax Radio on Wednesday.

"And now what I need to do is to ultimately go and get his DNA."

He said the claim was worth looking at as the person now aged in his 80s was connected to the Armstrong and Bartlett families.

Police have a DNA profile of the offender but testing in 1999 eliminated all eight prime suspects in the case.

Ms Armstrong was raped and stabbed 29 times and before being found on the floor in her bedroom.

Ms Bartlett was stabbed 55 times and her body found in the hall outside Ms Armstrong's bedroom.

Ms Armstrong's 16-month-old son was left unattended in his cot for two days before the bodies were discovered.

Det Sen Sgt Iddles also says he hopes to solve a three-decade-old murder before he leaves the homicide squad to take over as secretary of the Police Association on April 7.

He met a man who said he had information about the case at a football oval late at night.

"Over the last 12 months I've worked on that and I think that might be my swan song.

"We're coming up to 31 years and I'm fairly confident that before I take on the new role I'll have an arrest."

Det Sen Sgt Iddles did not specify the case but said the offender told the man that he did it.