Police were called to a shop on Oxford Street in Cambridge Park at 9.40am after a man and woman in their 60s were found dead by a family member.
The two people had suffered “significant injuries,” Acting Superintendent Michael Cantrell said.
“The family are obviously devastated and they are assisting police,” he said.
Police said the investigation was in its infancy with many lines of inquiry open.
They have not yet identified any suspects in the deaths.
Police said they had seen footage showing a male in the vicinity of the crime scene, but that the time had yet to establish if it was related to the deaths.
“All motives are being considered at this point in time,” Cantrell said.
“We have no intelligence to suggest that there’s any further threat.”
A crime scene has been established with officers seen outside the shop throughout the day.
Anyone with information is urged to contact Crime Stoppers.