Homicide Squad detectives set up a crime scene in Cochrane Street, Mitcham, after police were called to a house at about 3.40am and found the 37-year-old man dead.

The property was the scene of another violent crime in May last year when 76-year-old convicted killer Manfred Ulrich Kobert shot and seriously injured his 38-year-old housemate Matthew Lovitt.

A 46-year-old woman was at the house on Thursday assisting police as they tried to establish how the man died.

Despite initially saying the woman was in custody, police said later she had not been arrested.

The man and the woman are believed to have known each other.

Kobert was jailed for at least three years and faces deportation to Germany, where he was born, once released.

Police don't believe the previous shooting is linked to the man's death.