Detectives investigating the killing of a 70-year-old man in Bangor, Co Down, on Wednesday night have described his injuries as "horrific".
Mr Frederick Russell McMahon, from Abbotts Walk in the town, was attacked by at least one assailant as he walked home through a park behind Bangor Abbey at 11.15 p.m. The alarm was raised by a motorist who witnessed the assault.
When police arrived at the scene, Mr McMahon was able to speak to them briefly before being taken to hospital where he died shortly afterwards. No motive has been established for the attack.
Det Insp David Skelly described the assault as "a severe and concentrated attack" in which the pensioner sustained "horrific" injuries.
"It's an absolute disgrace. A murder investigation has been commenced, and the motorist's evidence is relevant for the purpose of the investigation. The injuries were sufficiently serious for him [Mr McMahon] to subsequently die," he said.
"I would appeal to any person, anybody who was in that area at the time or indeed any person who is aware of anything at all in relation to this matter to contact either myself or the CID office at Bangor RUC station," Insp Skelly added.
An Alliance Party councillor, Mr Stephen Farry, condemned the killing, saying it was imperative for the perpetrators to be caught as quickly as possible. "It is unclear whether this was a mugging or a person being set upon by a number of youths.
"However, there will be someone who knows the identity of this killer, and they have a moral duty to come forward with whatever information they have," he said.