James Brindley's parents have made an emotional appeal for anyone with information about his murder to come forward.
The 26-year-old was stabbed in the heart while he walked home after drinking with friends.
James' mother and father, Beverly and Mark Brindley, say they need to know answers after their sons death on Friday 23 June.
Nobody has been arrested in connection with the death.
Police hunting the killers of James Brindley have released CCTV of men they want to trace.
Detectives say they are keen to speak to two men in connection with the James Brindley murder investigation.
Police have praised four teenagers who helped a stab victim, as they walked home from their school prom.