Gang associates charged over murders

A woman and three men allegedly associated with the notorious "Brothers 4 Life" gang will remain behind bars after being charged with murder.

Police allege Amanda Crowe, 32, Farhad Quami, 32, Mumtaz Quami, 29, and 22-year-old Jamil Quami were involved with the shooting murder of Mahmoud Hamzy in Revesby Heights in Sydney's southwest last year.

Mr Hamzy, the cousin of notorious NSW prisoner and Brothers 4 Life boss Bassam Hamzy, was found in his garage just after midnight on October 29.

Meanwhile, Farhad and Mumtaz Quami were also charged on Monday with an additional count of murder for the roles they allegedly played in the fatal shooting of Joe Antoun.

Mr Antoun was shot at his home in Strathfield in Sydney's west on December 16 last year.

The convicted armed robber and extortionist was immediately shot up to five times when he answered his front door.

Homicide squad commander Superintendent Mick Willing said more charges were expected to be laid over the shootings.

"Rest assured, more charges will be laid in the future as we intend to hunt down and bring to justice anyone who was involved in these ruthless crimes," he said in a statement.

The four will remain in custody after appearing on separate charges at Burwood Local Court on Monday.

Crowe, Farhad Quami and Jamil Quami are all due to reappear at the same court in November.

Meanwhile Mumtaz Quami is set to reappear in December.