Police in Armagh city are investigating an incident yesterday evening in which a man and a woman were doused in flammable liquid and set alight.
The attack took place at about 9pm when a group of five or six men entered the house in the Foley Road area.
They doused the woman (21) and man (33) with the flammable liquid and set them and the house on fire. It is believed that the woman managed to escape from the house and raise the alarm.
The victims were taken to hospital and treated for burns.
The woman is said to be in a critical condition, while the man is seriously ill but stable.
As forensic experts carried out a full examination of the damaged house at Foley Road, detectives said they were following a definite line of inquiry. A sectarian or racist motive has been ruled out.
Detectives earlier described it as "a particularly nasty and vicious attack" and said they were treating it as attempted murder.
SDLP councillor Sharon Haughey, who lives in the area, said the attack was absolutely barbaric and that local people were shocked.
"Whatever reason those responsible try to use as a justification for this attack, we must be very clear that no one has the right to act as judge, jury and prosecutor by taking the law into their own hands," she said. "There is little or no support for vigilante courts here."
Dominic Bradley, the Newry and Armagh SDLP MLA said the attack was ferocious in intent and would send shivers down people's spines. "We all must live by the law of the land and those who think they are above that must realise otherwise," he said.