Police have launched a domestic-related murder investigation after three people died in a house fire in Lincolnshire that two women managed to escape from.

One jumped from a window at the back of the house while firefighters tackled the fire, according to locals, while another was rescued by neighbours. Emergency services arrived at the house in Kirton, near Boston, at around 3am on 1 January.

Three as yet unidentified British people – a woman aged 27 and two men aged 24 and 32 – were found dead after the fire was extinguished, police said, adding that they were not looking for anyone else in connection with the fire.

Neighbours came to the aid of those trapped inside the detached house when they saw flames shooting through the roof.

John Holland, 68, who lives opposite, was woken by his Jack Russell barking some time after 2am. “When I looked through the window, I could see flames reflecting in the windows,” he said. “So I quickly got dressed, went outside, and then I saw the fire in the big upstairs front bedroom window, on the left. The flames were coming up through the roof and it was well ablaze.”

He said: “There was no smoke in the downstairs, and we could see a lady in the downstairs window. So me and this other chap, we rushed over to the front door and we were telling the woman, ‘Open the door’.

“She said, ‘I can’t find the key’, so we looked around, I picked up a brick and we smashed the plate glass in the porch. We knocked all the sharp edges off and dragged her through and out.”

He added that the woman was extremely distressed, telling neighbours, police and firefighters there were still people inside. “She said, ‘There’s somebody upstairs,’ but then, just as she did, the whole roof above the upstairs bedroom caved in,” Holland said. “It spread and really got going then, all across the upstairs. It was really quick.”

Holland said another woman escaped by jumping from a window as firefighters battled the blaze. The fire caused every window on the upper floor to shatter and part of the first-floor wall to collapse. Both women have now been discharged from hospital.

Lincolnshire police appealed for witnesses and for anyone with information about the occupants of the house to contact them. A spokesman said: “It will take some time to formally identify them, but at this time we believe we know who they are, and their families have been notified and family liaison officers are in contact with them.

“We can confirm that we are treating this as a domestic-related murder investigation, but we are not looking for anyone else in connection with this.”

Neighbours told Lincolnshire Live they heard explosions and thumping when the fire took hold. David Brown said: “I went over this morning to see how the house was and I think they are probably going to have to pull it down … It is a devastating thing to happen in this community.”