Police investigating the murder of Michael Kerr have made a fresh appeal for information.
The 68-year-old was found dead inside his home in Bangor, Co Down, on 19 November.
Detectives believe he was subjected to a “vicious and sustained attack”, suffering “multiple blows to the head and body”.
They have released new CCTV footage showing two people who they believe may be able to help with the investigation.
Detective Chief Inspector Michelle Shaw said: “These two people can be seen on CCTV, walking along Birch Drive in the early hours of Monday 18 November at 4.41am.
“I believe that Mike was murdered sometime between 2pm on Sunday 17 November when he was last seen and Monday morning when he failed to leave the house according to his normal routine.
“These two people may have seen something important or may have information that could help me with my enquiries.”
Police said as Christmas approaches, Mr Kerr’s family are “still trying to come to terms with their senseless loss”.
DCI Shaw went on: “I still believe that answers to Mike’s murder lie within the community and I am appealing for the public’s help.
“Mike’s killers would have had bloodstained clothes – perhaps you have noticed someone you know acting strangely?
“If anyone has any information, no matter how insignificant it may seem, detectives can be contacted at Bangor PSNI station on 101.”