After an incredible career, one of the country’s greatest detectives has retired after 40 years of service.

Retired detective superintendent Peter Lennon sat down for an extended interview with Ray Hadley, who praised him for his remarkable contribution to policing.

“It’s hard to imagine,” says Ray, “any single police officer could’ve been involved in so many notorious, high profile murder cases as he was during his time.”

Hundreds of people lined the streets to pay their respects to Superintendent Lennon when he marched out of Fairfield Police Station for the last time on Friday.

He was involved in a number of high-profile murder investigations, including the killing of celebrated surgeon Dr Victor Chang and the 1987 murder of sex worker Jodie Larcombe.

Mr Lennon tells Ray how they eventually tracked down the killer, Daryl Suckling, after years of trying.

“We knew who it was, but we just couldn’t get enough to get it over the line.”

He says they eventually used listening devices to catch him bragging about the murder seven years later, and put him behind bars for life.

Click PLAY below to see Mr Lennon describe the investigation

Ray says the whole of NSW owes Superintendent Lennon a debt for his incredible service to the state.

“When you get up from that chair I’m going to give you a hug on behalf of the people of NSW and on my own behalf for 40 years of outstanding service in this state. You can’t have done any more.”

Click PLAY below to hear the extended interview