There were five men dead by December and others lucky to be alive following a series of brazen shootings that were carried out at any time of day in car parks, outside family homes and even one as guests left a wedding.

But two years on, and following one of the largest police investigations carried out in recent years, homicide detectives are one by one closing in on those responsible.

Detectives involved in the major operation, known as Strike Force Earp, believe all five murders and a series of other shootings were carried out by the one criminal group based in the city's west.

A key member of that group, a 28-year-old man who cannot be named for legal reasons, was arrested and charged with murder when homicide detectives visited him at Silverwater jail on Friday.

It followed the dramatic arrest of another member, a 27-year-old, as he walked out of a Sydney courtroom on unrelated drugs charges on Tuesday.

Both men have been charged with the murder of father-of-four Ali Eid, who was shot dead in a brazen daylight execution at Punchbowl in November 2012. Mr Eid was doing tiling work on the half-finished property he was building for his young family in Lumeah Avenue.

The men have also been charged with attempted murder relating to an electrician who also was working on the home. Mohammed Hanouf was shot but survived the attack.

Head of the homicide squad Detective Superintendent Mick Willing said the investigation, which has involved thousands of hours of reviewing security footage and interviewing unco-operative witnesses, was "far from over".

"We believe the same criminal group is responsible for all five shooting incidents and we plan to make more arrests and lay more charges in the near future," Mr Willing said.

Those other incidents include

• the fatal shooting of known drug cook Roy Yaghi, 32, and Jamie Grover, 26, as they sat in a ute at Wentworthville on August 30, 2012;
• the fatal shooting of Commanchero bikie member Faalau Pisu 23, and the wounding of two others as they left the wedding of another gang member at the Serbian National Defence Council at Canley Vale on November 5, 2012; and
• the fatal shooting of Mr Eid's relative, Bachir Ajra, 28, outside his family home in Punchbowl on December 18, 2012.

The members of this crime group have spent the best part of their adult lives in and out of jail, convicted of offences such as manslaughter, large-scale drug deals and armed robberies. Senior police have described them as more deadly and daring than the infamous Sydney crime group Brothers 4 Life.

While police believe the same group is behind all five murders, they do not believe the incidents are directly linked. The court was told on Tuesday that Mr Eid was killed over a drug debt.

It is understood that Mr Pisu was randomly hit when a gunman opened fire on a party leaving the wedding after someone was bad-mouthed during the celebrations.

Mr Yaghi, who had links to bikie gangs, was allegedly shot over a long-running dispute but his associate sitting in the car with him that night, Mr Grover, was collateral damage.

"This is a complex and challenging investigation but the detectives working on Strike Force Earp are some of the most tenacious police officers you will find," Mr Willing said.

"I have every confidence in the work they are doing and know that they will bring more people to justice in the months ahead."

The 28-year-old arrested on Friday will appear in Burwood Local Court on Monday.

His co-accused returns to court next month.