Police investigating the murder of Greenisland pensioner Eddie Girvan are probing a potential link between his death and the sex industry.
It is understood that Mr Girvan often met women, some of whom were sex workers, on dating apps and online dating sites.
It is not known if Mr Girvan was aware of their connection with the sex industry.
However, his involvement with them is currently a line of inquiry for detectives investigating his murder.
Over the past six months, Mr Girvan had signed up to at least two interactive dating apps, which are increasingly being used by those people within the sex industry.
Officers are attempting to establish if there is a link between Mr Girvan's lifestyle and his brutal murder.
The 67-year-old's body was found in his Station Road home on Monday night. His hands were tied and he had a stab wound to his chest.
The PSNI told the Belfast Telegraph last night: "Detectives are making inquiries into Mr Girvan's friends, associates and lifestyle to build up a picture of his activities in the days leading up to his murder."
Three people - a 29-year-old woman and two men aged 23 and 24 - remained in police custody last night on suspicion of murder.
Officers were yesterday granted an extra 36 hours by a court to question the woman and the 23-year-old man.
According to a police source, detectives are probing a number of theories as to what may have happened to Mr Girvan.
"There is nothing really making sense at the minute," the source added. "We are working to find a convincing theory."
The PSNI indicated on Monday that Mr Girvan's body was discovered by chance as police officers were investigating an unrelated incident.
When officers arrived at his house at around 9.30pm, they found the victim dead in a chair.
A post-mortem examination set to be carried out will establish the time of death.
Mr Girvan is understood to have had a number of CCTV cameras around his property, including on the porch and in an upstairs bedroom.
Detectives will be reviewing any footage that may have been recorded in recent weeks and days for clues.
Officers are also keen to trace the movements of Mr Girvan's silver Hyundai car, which was seen driving dangerously towards Belfast and was later found on Tuesday morning in the Verner Street area of the city.
Mr Girvan, a retired plumber, is believed to have lived in Greenisland for around 40 years and was a collector of antiques.
He was separated with two daughters. The senior investigating officer in the case, Detective Chief Inspector John McVea, said it was a "horrific and shocking" crime and added that Mr Girvan had suffered a "painful and violent death".
He indicated Mr Girvan was seen in a nearby off-licence at about 2.30pm on Sunday. However, his whereabouts and movements, or who he was with, are unknown beyond this point.
Mr McVea appealed for anyone who saw Mr Girvan in the last few days to contact police.
East Antrim Alliance Party MLA Stewart Dickson said that he had known Mr Girvan most of his life, having gone to primary school and to Boy's Brigade with him. "(He) was always a very helpful, friendly person, someone who would have gone the extra mile to help people, doing odd jobs and was always willing when somebody needed something done in their home, a repair job or something like that," said Mr Dickson.