Police say an electrical device started the devastating Mandurah caravan park fire which claimed the lives of a father and his two children.
Police Commissioner Karl O'Callaghan this morning said that the electrical device started the fire and that shortly after there was what sounded like an explosion but that no gas bottles exploded.
He said there were two gas bottles, one inside and outside the tent.
Georgie Spies, 13, died this morning in Princess Margaret Hospital and her father, 48-year-old Brett Spies, died a short time ago in Royal Perth Hospital.
Ben Spies, 16, died yesterday after the blast at their campsite at Timbertop Caravan Park about 3am.
Witnesses said residents at the Peel Street caravan park battled flames up to 15m high.
Mr O'Callaghan would not say what electrical device was thought to have started the fire.
Sharon Doyle, who was staying at a house next to the caravan park, said she could hear screaming.
"People were yelling out 'help, help me'," Mrs Doyle said.
"The daughter was more whimpering. It was just horrible. Trying to get those sounds out of your head is hard."
Caravan park resident Tony, who was staying there on holiday, said he and another man had tried to battle the flames with a garden hose.
"I ran around trying to find another hose but there was only one, so we just did what we could," Tony said.
Permanent caravan park resident Kevin O'Neill said the tragedy had sent shock waves through the property, which had about 40 or 50 permanent residents.
Ben, a talented full-back with Mandurah Centrals Junior Football Club, died in the blast.
Insp. Bill Munnee said the arson squad was working with gas and electrical inspectors to determine whether a gas bottle had caused the explosion and to prepare a report for State Coroner Alastair Hope.
The family had been staying at the caravan park for a week and had kayaks and other camping equipment with them.
Speaking on behalf of the children's mother and stepfather outside Princess Margaret Hospital yesterday, Insp. Munnee said they were "absolutely shattered and devastated".
"They want people to pray for them and give them moral support to help them through this," he said.
Barry Lawrence, who coached Ben at Centrals last year, said he was a "loveable kid" and "a bit of a larrikin" who always lit up training sessions.
"I watched him last year grow into a young adult," Mr Lawrence said. "I taught him for a short period but the relationship we built together was not only as a coach but as a friend.
"He was a good player and could have been a good player in the future."
Vanessa Wood, the manager of Ben's football team, said he was a "brilliant kid" who had never been in any trouble. "He was a genuine, quiet kid who was one of the politest people you would ever meet," she said. "He was extremely well-liked."
Friends used social networking website Facebook to pay their respects to Ben.
"I'll never forget you," Shenai Ellen Toussaint-Roil wrote. "You were the nicest, most caring person I know."
Another friend, Ryan Jones, wrote that Ben always had "a smile on his face".
Georgie was the only girl in her under-13s football team at Centrals and was aiming to be the AFL's first female field umpire, her former coach David Ullyett said.
He said she was tenacious and skilful on the field, with a kicking ability which was better than most of her male teammates, and had recently started umpiring.
"She's such a gorgeous kid and a really mature girl who always keeps her teammates in line," Mr Ullyett said.