Detectives investigating the murder of a 31-year-old man in his Bangor home at the weekend believe he may have known his killer.
Stephen Davidson's body was discovered in the living room of his house by a family member at 5pm on Sunday.
Police said that Mr Davidson had been involved in a "violent struggle" with his attacker, but they did not reveal if a weapon had been used.
They are awaiting the results of a post-mortem examination to establish the cause and time of death.
A 30-year-old woman and a 40-year-old man were arrested in the Bangor area shortly after 1pm on Monday for questioning in relation to the murder.
There was no sign of forced entry at the front of Mr Davidson's large, detached home, where he lived alone, on the town's Ballyholme Road.
Detective Chief Inspector Richard Campbell, from the PSNI's Serious Crime Branch, said that while he was not in a position at this time to say if drugs were involved or if Mr Davidson had let his attackers into the house, he confirmed that "all this will form part of the inquiry".
Mr Campbell added that the fact the assault happened in the house "may indicate it was someone known to (Mr Davidson)". Mr Davidson, who was believed to have been unemployed, was seen in the Newtownards Road area of Bangor at around 9.30pm on Saturday.
Police are looking to speak to anyone who may have been with him at any time between then and Sunday afternoon.
They also wish to speak to any residents in the Ballyholme Road area who may have witnessed activity around his house between Saturday and Sunday evening.
Forensic officers remained at the scene of the murder throughout Monday and could be seen carrying out work in the front living room of the property.
A number of items were removed from the house for forensic examination.
Searches were also carried out at several addresses across Bangor on Monday in relation to the murder. Neighbours have spoken of their shock at the killing.
One resident said: "My wife was very nervous when she saw the police cars at the house and then we heard there had been a murder. You never expect something like this to happen on your doorstep."
North Down MLA Alex Easton said he was "saddened" to hear about the murder.
"I would like to pass on my condolences to the young man's family. It is important that anyone with information which may be of use to police should come forward to help with the investigation. Those responsible must be brought to justice," the DUP man added.
His colleague Peter Weir described the murder as "despicable" and said that his thoughts and prayers are with Mr Davidson's family.