Two adults and an infant were killed in a house fire in Cwmbran, Gwent Police said. A 27-year-old man has been arrested on suspicion of arson.
Emergency crews were called to a blaze at Tillsland, Coed Eva, Cwmbran, south Wales at 3.30am on Tuesday.
Whilst tackling the flames firefighters discovered the three bodies.
Neighbours on the sprawling estate were in shock.
Sandra Gough, 64, lives a few doors away from the fire-ravaged home.
She said she believed the victims were a 16-year-old mother of one, who was known to be pregnant with twins who lived with her mother, aged about 46.
"I heard banging and screaming at about 3am. It could well have been somebody trying to force their way in or out of the burning house," she said.
"I would have tried to help if I'd gone out there, but I didn't know.
"I thought the banging was coming from the nearby primary school. They're doing work there and I just thought they were continuing through the night.
"I thought the screaming might have been young people in the street,
"At my age, when you live alone you think twice before going out in the dark.
"I just drifted off to sleep after a while and I thought no more of it. I suppose the noise must have died down."
She added: "It was only when I got up this morning that I heard what happened but I didn't realise it was so close.
"I saw all the ambulances outside and the house was still smoking. It is terrible, absolutely horrific."
A Gwent Police spokesman said: "The people confirmed deceased inside the address were two adults and one infant.
"Fire service and Gwent Police forensic investigations will begin this morning and officers will also be conducting house-to-house inquiries in the area.
"A 27-year-old man has been arrested on suspicion of arson with intent to endanger life and is currently in custody."