Homicide Squad detectives are investigating the death of a 52-year-old man outside a home in Perth's south.
Police say they were called to the property on Carrington Street in Hilton about 4pm yesterday, where they found the man collapsed on a footpath.
St John Ambulance paramedics and members of the public administered first aid but the man died at the scene.
A 44-year-old man has been arrested and will remain in custody pending the ongoing investigation.
Detectives want to speak to another man, who they believe drives a Toyota Hilux utility with the registration 1DOJ521.
Detective Inspector Quentin Flatman said police believed it was not a random attack.
"All three parties are connected to one another, they are known to each other, they have an established relationship," he said.
"There is no need for concern by any members of the community.
"We believe — as I say the investigation is ongoing — it resulted from a dispute at a house within that area."
Victim seen stumbling in street
Detective Flatman said witnesses had reported seeing the victim stumbling across the street before his death.
"The circumstances of how he was stumbling, what caused him to be stumbling remains unknown," he said.
The victim had no obvious injuries or cause of death.
"The circumstances of his death remain suspicious until we can actually rule anything out," Detective Flatman said.
Police said the Toyota Hilux was seen in the area between 2.30pm and 4.30pm.
Anyone with CCTV, mobile phone or dash cam vision of the area around Carrington Street in that time period has been urged to come forward.
Police have also urged anyone with any other information about the incident to contact them.
