Hillsborough County sheriff's Col. Donna Lusczynski. 
 
 Lusczynski said. Various small fireworks also were found throughout the house, she said. 
 
 Lusczynski . 
 
 The investigation and identification process likely will take several days, Lusczynski said. Authorities are exploring all angles of the case, including the possibility of murder-suicide, she said. 
 
 “We're continuing to process the scene,” she said. “It will take several days to complete this investigation. We can't come to any conclusions yet.” 
 
 Firefighters responded to multiple 911 calls reporting a fire at about 5:45 a.m. One caller reported hearing “popping” noises. In another call, a woman, obviously upset, told the dispatcher she was walking her dog when she saw that the house was engulfed in flames. 
 
 “The house just exploded,” she said on the recording. 
 
 Neighbor Ken Hoverman said he woke up to a bang that he didn't know where it originated. 
 
 “I'm right next door,” Hoverman said. “I heard a big boom. I didn't know what it was. Didn't know immediately where it was.” 
 
 He kept hearing multiple noises. He believes there was an explosion on the garage side of the home. The garage is on the north side of the house on the opposite of Hoverman's home. 
 
 “It was scary, believe me,” Hoverman said. 
 
 He said he saw the father and son at the fitness center a lot. He didn't speak to them, he said. He couldn't recognize the mother and daughter, he said. 
 
 He said the houses are separated and he never heard anything from the home. 
 
 “Very traumatic,” Hoverman said. “We're all very saddened.” 
 
 Firefighters remained on scene throughout the morning, as hot spots continued to flare up. A search warrant was executed at 3 p.m., and sheriff's office investigators entered the burned out structure. 
 
 The fire was contained to the residence and did not threaten other residents in the affluent North Tampa gated community, Lusczynski said. 
 
 Darrin Campbell is a member of the board of trustees at the school, and his two children are students there. Erma Ruffkess, communications director at Carrollwood Day School, said deputies had been in touch with the school Wednesday. 
 
 Several members of the school's board of trustees declined to comment when reached by telephone Wednesday. 
 
 Darrin Campbell previously worked at Anchor Glass Containers in Tampa, said a spokeswoman for the company. After that, he went to PODS in Clearwater, where he was the chief operating officer from 2005 until 2008, a PODS company spokesman said. 
 
 Deputies were not called to the Avila house during the two years the Campbells lived there, authorities said. 
 
 Mary Helen Smith, who lives a few houses away, said helicopters woke her up at about 6:30 a.m. 
 
 “I could hear them circling,” she said. 
 
 Smith and her daughter walked over to the scene around 8 a.m. and could still see flames toward the back of the house, she said. Her daughter had to park her car outside the gate because authorities weren't allowing anyone to drive into the neighborhood. 
 
 She did not know the Campbells, she said. 
 
 Blake, who is married and has a 2-year-old daughter, retired from competitive tennis in 2013 after a 14-year career. 
 
 In a 2007 interview with The Tampa Tribune, he said he was attracted to the Tampa Bay area beginning in 1999 as a training ground for his tennis career. Property records show he purchased the 5,856-square-foot house in Avila in 2005, the same year it was built. 
 
 Walter Godfrey, who has been president and senior fire and explosion analyst with Fire/Reconstruction Consultants in Cape Canaveral since 1981, said most houses built over the past decade, perhaps longer, have safeguards to prevent fires from spreading throughout the home. 
 
 Arson investigators have their work cut out for them in a house of this size, he said, as everything, from building materials to the sizes of rooms and what furnishings are there, must be documented as precisely as possible. 
 
 Godfrey, a former deputy fire marshal for the state of Florida, said investigators start wide and narrow down their search for a cause. 
 
 “Basically, we all have a systematic way to go through a fire scene,” he said. Outdoor inspections include measurements between windows and doors and indoors, investigators do the same, with an eye toward areas with the most fire damage. 
 
 That, he said, is where the fire likely started. 
 
 Staff writer Joey Johnston contributed to this report. 
 
 ebehrman@tampatrib.com 
 
 (813) 259-7691 ||||| Two adults and two teenage children were found dead in a Tampa Bay-area mansion fire that appeared to have been set intentionally Wednesday, officials in Florida said. 
 
 Investigators said they were not ruling out the possibility of a homicide or murder-suicide at the roughly 6,000-square-foot home, which is owned by former tennis star James Blake but which he had rented out and has not lived in for the last two years. 
 
 We have confirmed that there were also various fireworks -- small, commercial-type fireworks -- throughout the residence. - Hillsborough Sheriff's Office Col. Donna Lusczynski 
 
 The victims have not been positively identified as the family that had been renting the home from Blake, though officials said they had contacted their relatives to prepare them for the worst. 
 
 Blake, who announced his retirement at last year's U.S. Open, was apparently out of state during the time of the fire, according to the Hillsborough Sheriff's Office. 
 
 Neighbors first called 911 at 5:45 a.m. to report an explosion and the possibility of a fire in the well-to-do Avila subdivision, and when firefighters arrived, they found a ferocious blaze that took hours to defeat. 
 
 Once it was safe for investigators to make it inside of the home, they discovered the four bodies in separate bedrooms -- two adults in one bedroom and the two youths in two other bedrooms, according to Hillsborough Sheriff's Office Col. Donna Lusczynski. 
 
 Two of the victims had unspecified upper-body trauma, but Lusczynski wouldn't go into further detail, saying the causes of death have yet to be determined. 
 
 That wasn't the only discovery. 
 
 "We have confirmed that there were also various fireworks -- small, commercial-type fireworks -- throughout the residence," Lusczynski told reporters in a televised news briefing. 
 
 Lusczynski added that the fire was started by an unknown accelerant and said the fireworks may have been the source of the explosion heard by the neighbors. 
 
 She said it would probably take several days to identify the victims and that an investigation into the fire was underway. 
 
 Blake retired from professional tennis last year at the age of 33 after reaching a top-five world ranking at the peak of his career. 
 
 The Associated Press reported that Blake bought the five-bedroom, five-bathroom Avila home in 2005 for $1.5 million, according to Hillsborough County property records. 
 
 According to the AP, many well-known football, baseball and tennis players have bought homes in the exclusive subdivision, which has a country club and golf course.
– Four people were found dead in a Tampa Bay-area mansion owned by tennis star James Blake after an explosion and fire—and though the fire appears to have been intentionally set, authorities believe it wasn't what killed the two adults and two teenagers. A police spokeswoman says two of the bodies had visible upper-body trauma, and murder or murder-suicide is suspected, reports the Tampa Tribune. A couple and their two teenage children had been renting the house for the last two years but investigators haven't confirmed the identities of the four bodies. Police say the fire appears to have been started by an unknown accelerant and fireworks may have caused the explosion heard by neighbors, the Los Angeles Times reports. "We have confirmed that there were also various fireworks—small, commercial-type fireworks—throughout the residence," the spokeswoman says. Blake, who retired from competitive tennis last year at the age of 33, was at his home in Connecticut when the fire happened, his management company says.