DETECTIVES are hoping CCTV images will help people remember crucial details to help solve the murder of Jim Attfield.
Officers are looking to identify a man who had been walking by the lake just an hour or so before the attack.
Jim Attfield was found seriously injured with 102 stab wounds near Castle Park off Guildford Road shortly before 6am on Saturday, March 29.
He died a short time later at the scene.
The 33-year-old man from East Bay in the town was last seen in the River Lodge Public House on Middleborough on Friday, March 28.
He left there shortly after 10pm, never to be seen until he was found the following morning.
Det Chief Insp Simon Werrett, said: "This man can be seen wearing a hoody and holding a carrier bag as he walks through the park shortly before 1.30am.
"There has to be someone living in the town who knows this man or is even related to him.
"We urge to them to contact us so that we talk to him and find out what he was doing in the park and then hopefully dismiss him from the enquiry. We want to move on and concentrate fully on potential suspects.”
In total, seven people require elimination from the murder investigation.
Anyone with information is asked to call Essex Police on 101 or Crimestoppers anonymously on 0800 555111.
A man and a woman, both aged 27 and from Colchester, are currently on police bail until tomorrow having been arrested in connection with the murder.