Police hunting the killer of James Attfield, who was stabbed more than 100 times in an attack in a park in Colchester, have issued CCTV of 23 potential witnesses.
They are images of people who were in Castle Park in the hours before Mr Attfield was found dying.
The images, taken from a CCTV camera which overlooks the area of Middle Mill on the outskirts of the park, show people walking in the area between 11.45pm on Friday 28 March 28 and 4.23am on Saturday 29 March.
Senior Investigating Officer, DCI Simon Werrett, said: "I would ask anyone who may have walked in this area on Friday night or Saturday morning to take a look at the pictures and see if they recognise themselves. Even if they are not pictured I would ask that they still contact my team to see if they might have any information which will help our enquiry."
Essex Police want anyone wanting to contact the Major Investigation team to call the hotline number 01245 282103 between 6.30am and 8pm or 101 outside those times.