Neighbours used a sledgehammer in a desperate bid to break in and rescue at least three people who died in a deliberate house fire in Fermanagh.
A man aged 27 is being questioned on suspicion of murder after he was detained at the scene in Derrylin and transferred to hospital for treatment, police said.
Brave locals attempted to smash a window but were unable to get in and save generations of the family, Sinn Fein MP Michelle Gildernew said.
She added: “As somebody who goes to a house in good faith to try and help people and people die, that is just, it’s horrendous. It’s hard to take.”
Police said the fire started in the early hours of the morning.
The whitewashed rural bungalow in Derrylin, near the border with the Irish Republic, was destroyed in the blaze and the roof collapsed, leaving a shell surrounded by farm buildings and machinery.
The victims only moved to the area recently, a local priest said, and were members of one family.
They had previously lived in the Republic of Ireland and were originally from England.
Fire engines and police cars were coming and going from the scene for most of the day.
Ms Gildernew added: “I know that some of the neighbours had went to the house here this morning to try and rescue the family inside. They are badly shaken.
“I understand they used a sledge and tried to break a window to gain access but weren’t able to do that.”
Police Service of Northern Ireland (PSNI) Detective Superintendent Jason Murphy said: “At this time we believe the fire, which has claimed at least three lives, was started deliberately.”
The victims were members of the same family, Democratic Unionist leader Arlene Foster said.
Catherine Fee, 27, said her father Tom owned the rented house and had been contacted by a friend on Tuesday morning to alert them to the fire.
The student, who lives just a few minutes away, said: “She said there was a fire in the house and there was smoke coming from the roof.
“My dad got up and went down to check. He tried to get into the house. They (her father and a neighbour) smashed the windows in trying to get into the house.”
She added: “It’s just so tragic, it’s an awful shock.”
Northern Ireland Fire & Rescue Service (NIFRS) said officers took an emergency call about the fire at 7.14am on Tuesday.
The blaze occurred in a rural lane near the scenic Doon Road. It was “well-developed” when firefighters arrived in three appliances from Lisnaskea and Enniskillen, the service added.
Police tape sealed off the entrance to Molly Road. It is the only house on the lane, surrounded by farm buildings and fields.
“It is important that the cause of the fire is established but my thoughts and prayers are with all those in the local area, friends and the wider family circle as they struggle to come to terms with this terrible tragedy.”