The four men, aged between 20 and 25, were arrested simultaneously in police raids shortly before 6am.
The men were arrested at houses in Bonnyrigg, Macquarie Fields and Gregory Hills in south-west Sydney, and in the rural town of Orange, NSW.
Omar Elomar was shot dead in cold blood in south-west Sydney. (Supplied)
All have been taken to local police stations where they are expected to be charged with the alleged murder.
Elomar was shot on Miller’s Cabramatta Avenue on a Saturday night in February 2020.
Despite paramedic efforts to save him, he died at the scene.
Omar Elomar was shot by Miller on February 15, 2020. (9News) Omar Elomar was sitting in a car when he was shot dead. (Supplied)
Elomar was sitting in the driver’s seat of a car when he was shot.
An 18-year-old man has been charged with his alleged involvement in the death, but has since been acquitted.
Detectives from the State Crimes Command homicide team are investigating the alleged murder for two years.
Police will talk about the arrests this morning.