Homicide detectives have charged a 27-year-old man with two counts of murder after a woman and her brother were found dead in an apartment in the Perth suburb of Victoria Park.

Key points: The man was arrested in Perth's CBD a day after the bodies were found

The man was arrested in Perth's CBD a day after the bodies were found The woman and her brother were found dead in the unit late on Sunday

The woman and her brother were found dead in the unit late on Sunday Neighbours said they heard screaming and yelling in the hours beforehand

The bodies of Maree Collins, 66, and her 62-year-old brother Wayne Johnson were found in a unit late on Sunday.

The man, who was a neighbour of one of the victims, was arrested in the Perth CBD the following morning after a 17-hour manhunt.

Forensic investigators remained at the eight-storey Leonard Street building during the week where a large crime scene was established on the top floor.

Police set up a crime scene at the apartment block to gather evidence in their investigation. ( ABC News: James Carmody )

Neighbours described hearing screaming and yelling about 4:00pm on Sunday afternoon, before more than a dozen police cars arrived along with two ambulances.

Police said one of the bodies was discovered in the apartment a number of hours after the first body was found.

Information given to police on Monday morning led to the accused man's arrest about 9:00am in the city, just a few kilometres from the crime scene.

The Victoria Park man appeared in the Perth Magistrates Court today and was remanded in custody until his next court date.