Eight men have been arrested over one of Sydney’s gangland executions, more than a year after Mehmet Yilmaz was gunned down in the street.

The 29-year-old was shot at point-blank range in front of his fiancee while getting into his car in a St Marys street in the city’s west on September 9 last year.

Police said Yilmaz was not formally aligned with any gang although he was closely linked with one.

Homicide squad detectives say he was kidnapped and assaulted in the weeks before his murder.

Two men have been arrested over the kidnapping and another six were in custody over the murder, police said on Thursday.

One of the men charged over the kidnapping is alleged Lone Wolf bikie head Erkan Keskin, who appeared in Central Local Court last week.

He faces a string of charges including demanding property in company and knowingly giving false evidence at a hearing.

Keskin, who was arrested two weeks ago, is due in court again on Thursday.

Since Tuesday, five men, aged between 25 and 31, have been arrested at correctional facilities over the matter.

Detectives raided properties at Blackett, Meadowbank, Mt Druitt, Stanhope Gardens, St Marys and The Ponds early on Thursday.

Yilmaz’s death was part of a string of 10 underworld shootings and apparent revenge executions across Sydney from 2015.

The deaths included Mafioso kingpin Pasquale Barbaro, 35, who was executed outside an Earlwood home in the city’s southwest in November 2016.

Gangland figure and convicted killer Ahmad, 40, was killed on a rooftop car park of Bankstown Central shopping centre in April 2016.

His execution was believed to be in retaliation for the fatal shooting of Safwan Charbaji outside a Condell Park panel beater several weeks earlier.

A key suspect in the Ahmad murder, Hamad Assad, was killed at a St Georges Hall home last October.

Detective Acting Superintendent Jason Dickinson, of the homicide squad, said his officers were collaborating with the gangs squad to probe the various shootings.

“Each investigation has current and active lines of inquiry,” he told reporters in Sydney.

“We are not giving up; it’s only going to be a matter of time before arrests are made.”

More than 80 firearms, 12,000 rounds of ammunition and $400,000 worth of illicit drugs have been seized during the investigation.

Police urged anyone with knowledge of the shootings to come forward.

-AAP