The father of a woman murdered along with a man in a Belfast flat said his family has no idea why somebody would kill her.
The bodies of Caron Smyth (40) and Finbar McGrillen (42) were discovered in the living room of the property in the Ravenhill area.
Police have not yet confirmed the cause of the victims' deaths but it is understood they were stabbed.
A 33-year-old man remained in police custody last night as detectives questioned him in connection with the murders.
Ms Smyth was originally from Drumaness, just outside Ballynahinch in Co Down.
Speaking at his home yesterday afternoon, Ms Smyth's father Henry said the family was trying to piece together what had happened to his daughter.
"We don't want to say anything at this point as we don't know what has happened yet ourselves," he said.
"We have no idea. The body was only formally identified this morning."
Both families and police are awaiting the results of post-mortem examinations.
Alliance councillor Patrick Clarke attended secondary school with Ms Smyth.
"She was in the year above me at St Colman's in Ballynahinch," he said.
"When I heard the name I knew straight away. It's tragic."
The bodies of Ms Smyth and Mr McGrillen were discovered at Ravenhill Court, off the Ravenhill Road, at about 3pm on Friday.
Police officers found them after receiving a report from a member of the public regarding damage to the property's front door.
The 33-year-old man being questioned was arrested on Saturday.
It is believed the victims had been living in the flat.
Mr McGrillen is said to have previously lived in Castlewellan, having moved from south Belfast.
Detective Chief Inspector Una Jennings said the killer may have been in a relationship with one of the victims.
"We are treating this at the moment as a suspected domestic homicide," she added.
Ms Jennings said police did not believe the public to be at risk.
South Belfast DUP MLA Jimmy Spratt said the local community was reeling from the murders.
Adam Newton, chairman of the District Policing and Community Safety Partnership and a DUP councillor for the area, said the murders were "very worrying".
"This is a quiet neighbourhood and a brutal event such as this can strike fear into the community," he told the Belfast Telegraph.
"Whatever brought about this dreadful incident it will be a heartbreaking time for all the families and friends.
"I extend my sympathies to them at this sad time."
Police have appealed for anyone with information to come forward.
The bodies of Finbar McGrillen (42) and Caron Smyth (40) were discovered in a flat at Ravenhill Court on Friday afternoon. The alarm was raised after damage to the front door of the flat was reported by neighbours. Police said they believed the pair had been victims of a domestic-related incident.
Residents of quiet cul-de-sac left in dismay
Police officers have remained at the scene of an horrific double murder with a cordon still in place around the small flat in which a man and woman were slain.
Ravenhill Court is a small cul-de-sac made up of about a dozen neatly kept red-brick properties.
Most have festive decorations in their windows, reminders of the cruel timing of the murders – less than a fortnight before Christmas.
And those in the area were still welcoming and trusting yesterday afternoon, despite the double killing.
I asked a middle-aged woman in the estate if I could speak briefly with her and a friend.
Before I had even introduced myself she handed me a bag saying that would be fine, provided I escorted her into her home, just a few properties along from the murder scene.
Police have previously been very infrequent visitors to this quiet area, consisting mainly of older people and young families.
"I've been here 20 years and there's never been no crime in that time," 82-year-old Olive Christie said. "I'm always saying how quiet it is around here."
Ms Christie said the flat in which the murders took place had a high turnover of residents in the past year. She said she believed both Caron Smyth and Finbar McGrillen were staying in the one-bedroom property.
"They hadn't been there that long," she said.
"Usually when you meet people round here they speak over but they seemed keen to just keep a low profile."
Police have so far declined to comment on whether the victims were involved in a relationship.
They also haven't said how they died, with neighbours speculating they had been stabbed.
Residents told how forensic officers had combed the area for clues throughout Friday and Saturday.
It is understood the property may have been used for social housing.
Another neighbour said around 20 police officers were at the scene on Friday afternoon.
She said she watched as the victim's bodies were removed on Saturday afternoon.
As at the Belfast flat, the blinds were also drawn at the home of Ms Smyth's parents in the small village of Drumaness, four miles from Ballynahinch.
Her father declined to speak at length about his daughter.
One said: "Caron's parents are very decent people. It's awful."
SDLP MP for South Down, Margaret Ritchie, said the double murder was devastating for the people of Drumaness.
"Such a tragic loss is devastating at any time of the year, but it is even sadder so close to Christmas," she said.