“Everything was quiet on Friday night and then all of a sudden all hell broke loose”
The dead man originally came from north Belfast.
Residents in Barna Square, Rathcoole – around four miles from Belfast – say police raced to the terraced property shortly after 8.15pm on Friday.
The police action followed reports that a man had been seriously assaulted inside one of the flats.
Film footage seen by the Sunday World revealed a half-naked man inside the property with blood streaming from a serious wound to his head.
He was being questioned by a PSNI officer as he sat on an internal staircase.
But minutes later a 24 year-old man was arrested inside the building and he was removed from the scene.
Eyewitnesses say that as he walked down the path to a waiting police car, blood was clearly seen streaming down his front and back.
It is understood the lifeless body of Mr MacNab remained inside.
Although officers applied first aid, he died soon afterwards.
Around midday yesterday, scene-of-crime officers arrived at the three-storey property to begin the task of collecting forensic evidence.
Officers from the PSNI Major Investigation Team also attended the crime scene, which has been sealed off. Children’s toys could be seen in the small front garden of the property.
A woman who lives nearby told the Sunday World that the entire neighbourhood was still in shock.
“Everything was quiet on Friday night and then all of a sudden all hell broke loose.
“There was a lot of noise and clearly someone was in grave danger. Then it all went quiet and we all thought it had settled down.
“But all of a sudden the police were running all over the place and we knew something was seriously wrong.”
She added: “We are all still in shock.”
Detective Chief Inspector John Caldwell said police responded to call for officers to attend a disturbance at Barna Square around 8.15pm on Friday.
And Detective Chief Inspector Anthony Kelly said: “I am continuing to appeal to anyone who believes they may have information which could assist detectives with their investigation to contact us at the Major Investigation Team on 101 quoting reference 1779 of 21/10/22.
“I will add that we are aware of footage from the scene circulating and would ask people not to share this out of respect for the family.”