An elderly widow murdered in her home in Melbourne's west was so concerned about a dispute with another person she reported the matter in person to police.

That report, on March 23 at Keilor Downs police station, was the last confirmed sighting of 77-year-old Vicki Ramadan before she was found dead in her Sydenham home by a neighbour on April 6.

Vicki Ramadan was found dead in her Sydenham home on April 6. Credit:Victoria Police

In a renewed push for information, Detective Inspector Tim Day said on Wednesday the person involved in the dispute was their prime suspect.

"We have a suspect, we have what we believe to be a motive for the murder [and] we believe we know what the dispute was about," the detective said.