Man seen before Melbourne body found

A man was seen at the Melbourne home of a woman just minutes before her body was found.

Traci O'Sullivan's body was discovered by her former partner and five-year-old son at her Frankston home on Saturday.

Homicide squad Detective Inspector Mick Hughes said a man believed to be in his 20s was in the driveway of the home when the former partner arrived.

"We have no suggestion at all that this person's involved so it's crucially important for us that we can eliminate him from our investigation," he said.

"But even more importantly he may have information or evidence that may assist us without inquiries."

The man is described as blonde and about 175cm tall, and was driving a black Mazda 3 hatchback.

Ms O'Sullivan was seen alive on Thursday afternoon. Det Insp Hughes said a post mortem was being carried out to determine cause of death but said she had been assaulted.