POLICE are confident it is just a matter of time before they solve the mystery behind Shandee Blackburn's murder.
Mackay District CIB Detective Senior Sergeant Rodd Carroll said at this stage they didn't have any suspects.
"We're confident that we can bring this to a head and get a result," he said.
"From our experience we don't believe it to be a random attack but then again that can't be ruled out at this point in the investigation."
Yesterday police released further CCTV footage (which can be viewed on dailymercury.com.au) of possible witnesses to Shandee Blackburn's murder.
Det Snr Sgt Carroll said the images were of two cars that were captured on CCTV footage while travelling on Juliet St, at 12.12am, on the night of the murder.
"We have been unable at this point to identify the owners of those cars and more importantly the occupants," he said.
"They are potential witnesses in the matter and we just want to speak to the drivers or occupants of those cars because there may be something that they've seen that means nothing to them, but it could be very crucial to us."
Investigators are also trying to locate Shandee's handbag.
"At this point in time the bag's outstanding and we want to find it," Det Snr Sgt Carroll said.
Police have released an image of Shandee as she left work at Harrup Park, carrying the bag.
They have also released an image of a handbag similar to the one she would have been carrying when she was attacked.
Anyone with information about the occupants of the two vehicles or the location of Shandee's handbag is urged to call Crime Stoppers on 1800 333 000.