Gardaí in the Togher district are appealing for information from the public about the murder, which is believed to have occurred in the early hours of Saturday morning.
A suspect was seen between Riverstick and Belgooly early on Saturday and is believed to have walked from Cork city to Kinsale at about 5.30am.
Gardaí are hoping to receive information about further sightings and believe that, despite the early hour, members of the public such as taxi drivers, security workers or truck drivers must have seen the man.
Detectives involved in the case are satisfied they have the murder weapon — a kitchen knife — used to stab John Hyland, 69, at his home in St Francis’s Avenue off College Road in the city.
However, they are keen to piece together a timeline of the events which occurred after 11.30pm on Friday, the time when Mr Hyland returned to his home.
It is understood that investigators are keeping an open mind but, following the hospitalisation of a 26-year-old man in a secure facility at the weekend, are not looking for anyone else. The man has a history of medical problems.
Speculation that the suspect was being kept under guard was dismissed by authorities but it could be weeks or even months before he can be questioned about the murder.
Superintendent Barry McPolin, leading the investigation, refused to comment about the man in hospital.
“We’re following a number of lines of inquiry and the investigation is progressing well,” he said.
Members of the Garda Technical Bureau continued their examination of the Hyland house yesterday after gardaí secured extension of time for crime scene designation.
Father-of-five John Hyland’s body was discovered by his wife, Maeve, at 1pm on Saturday. She had been babysitting one of her grandchildren on Friday night.
Mr Hyland was well known and respected in Cork business circles and the family were known for their work for the Special Olympics movement. The couple’s twin daughters were born with disabilities.
His body has remained at Cork University Hospital for a postmortem examination by state pathologist Dr Marie Cassidy since Sunday morning. Gardaí were unable to say when his remains would be released to the family for burial.
Witnesses should contact Togher Garda station on 021-4947120.