The family of a conservationist who was found dead after taking his dogs for a mountain walk have appealed for help in finding his killer.
Michael McCoy, in his 60s and a leading member of the Dublin Mountain Conservation and Environmental Group, is understood to have died after suffering a head injury while on an early morning outing last Thursday.
His body was found by search teams at about 4am on Friday morning.
Mr McCoy's artist niece Kirstin posted a number of messages online, including a plea for information on his death.
"I hope and pray that the perpetrator of this horrendous crime is caught ASAP. Anyone with info please contact Garda. Dublin Mountains Murder," she said.
Ms McCoy said she was in total shock over her uncle's death and described him as a kind and gentle man.
Mr McCoy, from Ballinascorney Upper, near Brittas in south Co Dublin, took his two boxer dogs for a walk in the nearby mountains at dawn last Thursday .
His body was found the following day near a track in a forest area on Ballinascorney Hill.
Mr McCoy's daughter Rachel also took to social media in the aftermath of his death as the family searched for one of the dogs which has been missing since.
One of the animals returned to the family home but the missing dog, Fia, a distinctive tan-coloured boxer with a long tail, did not, and a reward has been offered for her return.
Mr McCoy acted as secretary of the Dublin Mountain Conservation and Environmental Group and his name was attached to many actions taken by the organisation over planning, environmental and development issues in the area.
He was known for being passionate about protecting the natural heritage of the Dublin Mountains.
A 41-year-old man arrested by gardai on Saturday in connection with the killing was released without charge.
A Garda spokesman said a file was being prepared for the Director of Public Prosecutions.
Mr McCoy was reported missing on Thursday and a search was carried out overnight by members of the Dublin Wicklow Mountain Rescue Team and the Glen of Imaal Red Cross Mountain Rescue team.
Gardai at Tallaght are investigating the murder and have appealed for witnesses, including anyone who was in the general area of Ballinascorney Hill or Ballinascorney Road Upper from 6.30am last Thursday until 4am on Friday when the body was found.