They have been asking for information about a silver and blue Mitsubishi L300 van seen near Mr McMurdo's address close to the time he died.
Yesterday Detective Sergeant Roger Small told the Herald a second car may be linked to the murder.
The silver 1987 Mitsubishi Mirage, registration SA2782, was stolen from a property in Massey, West Auckland on or about July 27 last year.
It was driven around the Auckland area for several days and then driven to Northland on or about July 31 last year.
"The vehicle has recently been recovered from Northland, sporting damage believed to be caused by striking a cattle beast in the Wellsford area on the trip north in late July 2011," Mr Small said.
He could not give any further detail about the relevance of the car to the investigation, but said it was important for anyone who had seen it to contact police.
Mr McMurdo was well known in the Helensville community.
After he died police acknowledged he had become involved in the local drug scene, attracting their attention when he was charged with cultivating cannabis.
Soon after the killing, Mr McMurdo's father, Bruce McMurdo, made an emotional appeal for information about his son's murder.
"Lee died a violent death and, although he appeared to be on the wrong side of the tracks when he was killed, it wasn't always so," he said.
"He fathered three wonderful children, was a skilled golfer and was well loved and liked by many. But ... he got caught up in a drug scene. That doesn't mean he deserved to die the way he did."
CAN YOU HELP?
Anyone who saw this silver 1987 Mitsubishi Mirage after July 27 last year should contact the Operation Manu team on 0508 00 6268 or opmanu@police.govt.nz. Alternatively anyone with information can call Crimestoppers anonymously on 0800 555 111.
