Man charged over Sydney gangland murder

A third man has been charged over the "sophisticated and well-planned execution" of Sydney crime boss Mahmoud "Brownie" Ahmad.

NSW Police officers from Strike Force Erebus arrested 26-year-old Pierre Abou-Sleiman in Campsie on Wednesday and charged him with murder and participating in a criminal group.

He did not apply for and was formally refused bail at Bankstown Local Court on Thursday.

Homicide Squad Commander Detective Superintendent Danny Doherty said that while the Abou-Sleiman was not the gunman he was allegedly directly involved in planning the murder.

"We are alleging he was part of a sophisticated and meticulous planned murder plot," Det Supt Doherty told reporters on Thursday.

Abou-Sleiman is set to reappear at Bankstown Local Court on January 19.

Ahmad, 39, was gunned down on the street in Greenacre in Sydney's southwest in April, six months after being released from jail, having served five years for the manslaughter of gangland rival Safwan Charbaji.

At the time detectives described the hit as another brazen and callous chapter in Sydney's ongoing gang wars.

He had been warned underworld enemies placed a $1 million bounty on his head.

His brother and crime kingpin Walid "Wally" Ahmad also died in a hail of bullets while sitting at an outdoor cafe at Bankstown in 2016.

Det Supt Doherty said Ahmad's murder would not have happened without careful planning and co-ordination.

"It takes a number of people ... to commit a sophisticated and well-planned execution of an organised crime figure," he said.

The accused man had fled overseas shortly after being questioned by police in May, before returning on October 31.

"So the message is, whether you go overseas or go interstate or you stay where you are police will still ... work tirelessly in relation to building evidence," Det Supt Doherty said.

Police would be "unrelenting" in hunting down people involved in organised crime murders, he said.

In July, NSW Police arrested a 37-year-old they alleged was involved in planning Ahmad's killing, a month after a 49-year-old man was charged with being an accessory before and after the fact to the murder.

The investigation is part of ongoing inquiries by Task Force Erebus into 14 fatal shootings and criminal activities by organised crime networks across Sydney.