The investigation into why a million dollar mansion burned down and four bodies were found inside has begun to center around the actions of Darrin Campbell.
Campbell’s body was found Wednesday in the Avila mansion along with those of his wife and two teenage children.
Hillsborough sheriff's investigators have tracked his movements in the days leading up to the fire.
Security camera video shows Campbell buying $600 worth of fireworks Sunday, the same fireworks sheriff’s spokeswoman Donna Donna Lusczynski said were placed throughout the mansion.
"The fireworks could have been used to ignite the keep the fire aflame,” she said.
She said Campbell bought several cans for gasoline at a local home improvement store. Investigators found his gun inside the home. They say all four bodies taken from the mansion had been shot
People who knew the Campbells say they seemed like a very happy family. Former neighbor Janelle Vann said, "Definitely very shocked by the whole thing."
Psychiatrist Walter Afield does a lot of work with serial killers and the mentally ill. He said if this was a murder-suicide the murderer would have been very disturbed.
"In terms of people who commit this kind of thing, usually there is a screw loose pretty badly,” he said. “It doesn't look like it from the outside, but when you scratch beneath the surface you see there is something really crazy."
He adds losing a job or an economic hardship might cause someone to kill themselves but not an entire family, especially one in which the children were so well liked with a bright future.
Investigators are also going over Campbell's financial records to see if those add clues to a motive for the deaths.