Police have released CCTV footage of two people they want to speak to about the murder of Michael Kerr (68) in his Bangor home last month.
Mr Kerr had been subjected to a sustained and vicious attack and received multiple blows to his head and body, police said.
Detective Chief Inspector Michelle Shaw said: "As we approach Christmas, Mike's family are still trying to come to terms with their senseless loss.
"I am continuing to establish a motive for Mike's murder but his family are still lost for answers as to why this happened to their loved one."
She released CCTV footage of two people she believed may be able to assist her with her investigation.
"These two people can be seen on CCTV, walking along Birch Drive in the early hours of Monday 18th November at 4.41am.
"I believe that Mike was murdered some time between 2pm on Sunday 17th 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. I would ask for these two people to contact police ... I would also ask the public to get in contact if they recognise these individuals."
She said answers to his murder lay within the community and appealed 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."
