A neighbour has been named as a suspect in the alleged murders of a Perth brother and sister after he was caught in the CBD fleeing the crime scene on Monday morning.

State Crime Commander Allan Adams said police were called to the complex on Leonard Street in Victoria Park about 4pm on Sunday.

Police are at the scene talking to neighbours. Credit:Kate Hedley

The caller, believed to be family of the 62-year-old brother and the 68-year-old sister, reported a disturbance at the address and on arrival police found one body inside the building.

It is understood there had been some effort to hide the body, and although police initially reported only one deceased person at the address, a second body was located shortly after.