Police are pleading for information about the murder of an elderly Melbourne man, violently bashed while alone at home.
Kon Kritikos, 87, was attacked in his Reynard Street, Coburg property on November 11 between 3.30pm and 5.30pm.
He died from his injuries two weeks later on November 24.
Detective Inspector Tim Day from Victoria Police's homicide squad faced media on Saturday to make an appeal to anyone with suspicions or evidence.
"Here we have an 87-year-old man, vulnerable, home alone, his wife in hospital, relying on the help of others to survive," he said.
"A man of impeccable character, much loved, who's worked hard, paid his taxes, contributed to society his whole life, only to have that life snuffed out by a heartless, cowardly and callous thief."
There was no forced entry to the property, causing police to believe the person who entered was someone the victim knew.
"Someone he knew, someone who knew that he was alone at that time ... someone able to gain easy access to the home," Det Insp Day said.
Mr Kritikos lay seriously injured after the attack for about five hours until his son, 57, from Coburg and a female, 45, from Kurunjang, visited the home at 11pm that night and called for an ambulance.
Detectives believe the female who came in with Mr Kritikos' son was the same one who witnesses had seen entering the house on her own during the afternoon, and she is a suspect, Det Insp Day said.
He gave a strong warning to the killer that detectives are confident they will find out who committed the crime.
Police are asking for any family and friends who have been given a version by someone else of what happened, to contact them.
Witnesses or anyone with information or suspicions about the attack should contact Crime Stoppers on 1800 333 000.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14