Investigators were continuing to process the scene of a fire at a million-dollar home owned by former tennis star James Blake where the bodies of two adults and two teenagers were found.
The fire early Wednesday inside the Tampa home was intentionally set, officials said.
Two of the victims appeared to have upper body trauma, the officials added.
Hillsborough County Sheriff's Col. Donna Lusczynski said various fireworks were also found throughout the residence.
The home was being rented by the Campbell family, which has not been heard from since the fire.
"However, we have not been able to positively identify the bodies," Lusczynski said.
Police were still trying to piece together a possible motive.
The family has rented the posh 7,600-square-foot, $1.5 million mansion from Blake for the past two years. The property is located on the exclusive Avila Golf Course. Many well-known athletes live in the community, including former NFL player and coach Tony Dungy.
A former neighbor, George Connley, said Darrin Campbell was the treasurer of Carrollwood Day School, a private school attended by the Campbells' teenage children, Colin and Megan.
"They were a very nice family. We know nothing of any problems," Connley said. "The kids were outstanding children. This is very difficult to put our arms around."
He said that Kimberly Campbell was "sophisticated and classy."
Blake, 34, was ranked fourth on the ATP world tour in 2006. He retired last year. He also has the James Blake Foundation, an organization dedicated to cancer research in memory of his father, who died of gastric cancer.
Blake's agent, Carlos Fleming, told The Associated Press that Blake was not in Florida. He declined to comment further.
The Associated Press contributed to this report.