A group of men arrested after a man was killed during a home invasion in Melbourne's west have been released without charge.
Police spokeswoman Kate Fawcett said the investigation into the man's death, at a house in Billingham Road, Deer Park, on Sunday, was ongoing.
Police would not disclose how many people were arrested and subsequently released, citing "operational reasons".
Police examine the scene of the attack in Deer Park. Photo: Jason South
Homicide detectives were called to the house about 10pm after neighbours heard screams and breaking glass.
A 20-year-old Diggers Rest man was found dead at the scene. Another man was taken to hospital with cuts to his hand and a woman was treated for leg injuries.
Police believe a group of more than 10 men had forced their way into the house, where seven people were inside, to inflict "as much damage and injury as possible". The assailants may have been wielding machetes and other weapons, according to police.
A neighbour reported seeing a group of men carrying metal bars, timber and possibly baseball bats outside the house just after 9.30pm. The neighbour said the men "rushed the house" in two stages.
"It was very well organised, very short, sharp. They knew what they wanted to do and they did it," said the neighbour, who did not want to be named.
"Within 60 to 90 seconds they were all out the front again. They gathered for 10 or 15 seconds, words were exchanged between themselves and then, for some reason, they went back inside again. There was a lot of screaming."
The neighbour said the group of men left the house and jogged away.
Detective Sergeant Paul Tremain said police believed the attack was not racially motivated and that the group members, who are all believed to be aged in their late teens to late 20s, were known to each other. He described the attack as "very quick … it was almost a case of running into the property, inflicting as much damage and injury as possible and running out of the property."