They released still images showing two men, a male and female couple, a person in a black-hooded coat, a woman in a dark coat, and a hatchback car.
Mr Miller said it was vital police could account for all movements on Boulcott St between 5.20am and 5.45am on December 10.
"We would really like to speak with these people to ascertain if they saw or heard anything at that time," he said.
"Whilst arrests have been made in connection to Mr Cottrell's death, this investigation is far from over and we need assistance from the public to help us piece the jigsaw together."
Mr Miller said police were still getting a good response from the public, with a steady number of calls and a number of people had been "extremely helpful" to the investigation.
Anyone with information was urged to get in touch with police.