Police and fire crews responded to the house fire at 7:25 a.m. Friday, according to police.
At 7:32 a.m., police, who were already on the scene, received a request from an undisclosed source to check the welfare of Broadhurst, police said Tuesday.
Investigators found accelerant in several spots in the suburban home, said Fire Authority battalion chief Brian Anderton.
Broadhurst died Friday night at the University Hospital burn unit in Salt Lake City, according to a statement issued by his family that also thanked medical personnel who assisted him and asked for privacy during the grieving process.
An investigation was continuing. However, authorities don't expect to find more evidence because the blaze gutted the home, Anderton said.
"With the fuel that was used to light it, it almost had an explosive property," he said without elaborating.
The fiery blast sent debris crashing into nearby homes, and authorities ordered evacuations as a precaution. Glass, toys and debris littered the yard.
Sean Miner, who lives next door to the charred home, said he heard a boom and saw an injured man stumble to a screen door and fall.
The man was covered in soot and blood, he said. Helicopters and fire crews arrived moments later.
David Politis, who lives a block away, said he heard the blast and ran to help. He saw two men surrounding another whose clothes had burned off. He gave a blanket and water to the injured man before crews arrived, he told The Salt Lake Tribune.
The Associated Press contributed to this story.