A man who was rejected by his teenage girlfriend has been found guilty of killing her, her seven-year-old brother Marcus, 10-year-old sister Patricia and their stepfather, Roddy Hine, 44 after the break-up of their relationship.
They all died when fire ripped through their home in Staffordshire, England.
Mark Goldstraw denied playing any part in the blaze, which broke out shortly before midnight on March 9.
However, the prosecution alleged the 31-year-old used at least five litres of petrol to start the fire.
Mr Justice Mitting sentenced Goldstraw to life imprisonment and ordered that he serve at least 35 years in prison before being considered for parole.
A statement on behalf of Ms Carter, who was at work at the time of the fire, was read to reporters by her sister, Tracey Cooper.
The statement read: “When I was told what had happened I just didn’t believe it. It was a short time before I could take it in – everything had gone, the children, Roddy, it had all disappeared.
“For a parent to lose one child is devastating, but three can’t be put into words.”
Ms Carter said her partner and the children were very close and had been “just great together”.
The grieving mother added: “They had their whole lives to look forward to and this has been cruelly cut short.
“Mark Goldstraw has been convicted of a terrible crime against four lovely people – his punishment will never fit his crime.”
The children’s natural father, Mark Carter, also issued a statement, which was read out by Staffordshire police press officer Neil Spencer.
Mr Carter, a 40-year-old fitter who lives in Leek, stated: “My life has been turned upside down. I will never forget being woken by the police banging on my door just a couple of hours after it happened. They asked me to sit down and said that what they were about to tell me probably wouldn’t sink in at first.
“I just went numb. I hadn’t seen Patricia and Marcus for two years because of me and their mum separating.
“Now I’ll never see them again…the fact that they have been murdered just rips me apart.”
Mr Carter described his children’s funeral as the hardest day of his life and said it would haunt him forever.
“Now I can hardly sleep at night – I have nightmares and all I see is my children screaming for help,” he said.”
Speaking on the steps of the court, the officer who led the investigation condemned Goldstraw as an extremely dangerous man.
Detective Chief Inspector Dave Garrett told reporters: “This was no spur-of-the-moment crime. He waited until his four victims had gone to bed before letting himself into their house, dousing the hallway with petrol, and setting it alight.
“He fled the scene of utter devastation, but left a trail of evidence which singled him out as the killer.”
The officer said Samantha had been plagued and pursued by her killer in the weeks before the fire.
“Our inquiries quickly pointed to Goldstraw as the main suspect,” Mr Garrett continued. “He was arrested just nine hours after starting the fire, yet time and again during interview, he refused to talk. His silence was damning.”
The officer praised colleagues who worked tirelessly on the case, including family liaison officers who supported the children’s mother and Mr Hine’s partner, Amanda Carter, following the murders.
“No amount of training can properly prepare you to investigate the killing of four people, three of them beautiful children,” Mr Garrett said.