New lead in Sydney security guard shooting

New CCTV footage and photographs have been released of two people wanted over the fatal shooting of a security guard in Sydney's CBD five years ago.

Gary Allibon, 59, was shot in the back and had his gun stolen when three men robbed a cash delivery van on Sussex Street about 6.10am on June 7, 2010.

The robbers escaped in a silver high-performance Audi S8 sedan driven by a fourth man and the car was found burnt out in a car park in west-suburban Milperra two days later.

Detectives have established links to three other shootings in Sydney and have released new footage of the car exiting the M5 at Henry Lawson Drive just before 10pm on June 9, 2010.

They are now trying to identify two men seen in a Mercedes C63 travelling behind the Audi.

Detective Acting Superintendent Mick Sheehy says the gun used to shoot Mr Allibon was also used in two other shootings at Vaucluse in 2007 and Merrylands in March 2010.

Bullet casings found in the burnt out Audi matched the shooting and wounding of Roy Yaghi at Wentworthville in April 2010.

A $100,000 reward remains available for information leading to the arrest and conviction of those responsible for Mr Allibon's death.