One man has been shot dead and another is assisting police as homicide detectives investigate a shooting at a rural property south of Perth.

Major police resources were sent to a property on Scarp Road in Keysbrook, about 73km south-east of Perth, following reports of a person with critical injuries about 8.40am on Saturday.

A mother in her 40s and her child were inside the residence at the time of the incident, police said. They both safely evacuated without injury.

“Significant police resources were deployed to the area, and, upon arrival, officers located a 44-year-old man deceased inside the residence with injuries consistent with a gunshot wound,” a police spokeswoman said.

“A 38-year-old man, known to the victim, was located inside a parked vehicle at the property. He was promptly apprehended and is assisting with inquiries.”

Police seized one firearm found at the property.

Following the arrest, police said there was “no ongoing threat to public safety” and that the incident was contained to the property.

Blue and white police tape cordoned off the Hilltop Orchard residence from the top of the dirt turnoff on Scarp Road by 10am, with several police cars and an ambulance in the driveway.

Armed officers were seen searching the outbuildings on the property about 10.20am, when a woman emerged with her hands in the air.

About an hour later, police could be seen walking out a woman and child down the driveway. The woman was dressed in a blue forensic jumpsuit and the pair got into the back seats of an unmarked police car before it drove away.

Detectives were seen outside a larger building on the property, with about a dozen police vehicles and ambulances nearby.

The homicide squad are investigating the incident and urge anyone with information to contact Crime Stoppers on 1800 333 000 or by making a report online.

Information can be provided to police anonymously.