The attack happened in Kirkistown Walk in the Belvoir Estate on Wednesday
Police have taken an unusual step in naming the man arrested on suspicion of the murder of a senior loyalist in a south Belfast as Albert Armstrong.
Colin 'Bap' Lindsay, 47, a well-known member of the Ulster Defence Association (UDA), was killed in an attack on Wednesday.
Another man is in a critical condition in hospital after the incident that happened at Kirkistown Walk in the Belvoir housing estate.
Police believe a sword was used.
It is not believed there was any paramilitary link to Mr Lindsay's killing.
Mr Lindsay and Mr Wightman were found in the living room of a house at Kirkistown Way
Mr Armstrong, 46, was arrested after police received a call from a concerned member of the public at 19:59 BST.
A samurai-type sword was found in a blue Mazda car nearby.
Police then found two men seriously injured in the living room of another house in the estate.
The ambulance service was called but Mr Lindsay was pronounced dead at the scene.
Stanley Wightman, the other victim of the attack, was taken to the Royal Victoria Hospital where he underwent surgery.
The 52-year-old has "significant injuries" to his neck and arm, police have said.
Police said the attack had been "extremely violent" and Mr Lindsay was pronounced dead at the scene
Det Ch Insp Richard Campbell said the attack had been "extremely violent".
"I'm taking the unusual step of naming the three men involved, because I believe that it's important to do that as part of my appeal for information from the community," he said.
"We want to hear from anyone who saw or spoke to Colin Lindsay, Stanley Wightman or Albert Armstrong at any time yesterday or who knows anything about their movements.
"At this stage, I'm very clearly working on the basis that this appears to have been of a personal nature, rather than having anything to do with paramilitarism."
Insp Campbell said he believed the sword recovered near the scene of the killing was "likely... the weapon that was used in the attack".
When asked if the sword belonged to Mr Lindsay, the detective said: "I believe it was in his property, yes."
Police do not believe there was any paramilitary link to Mr Lindsay's killing
Neighbours said the victim had been drinking in his garden with friends before the attack and the atmosphere had been jovial.
Insp Campbell added: "Mr Lindsay was known to police, but that shouldn't take away from the fact that he has suffered a very brutal death, completely unnecessary.
"He is a father of 12-year-old and 18-year-old girls and he is survived by his mother, all of whom are grieving his loss today."
South Belfast DUP MLA Jimmy Spratt said he was horrified by the killing.
"All indications are that it has been a pretty gruesome murder," Mr Spratt said.
"I want to give sympathy to the family concerned, because there is a family grieving behind the scenes."
