Flames engulf a house owned by former tennis star James Blake in Tampa, Florida. Picture: Hillsborough County Sheriff's Office, via Reuters

St Petersburg, Florida -

The “unusual” fire at a Florida mansion belonging to a former tennis star was intentionally set and a family of four was discovered in the charred remains, police said on Wednesday.

The victims were described as two adults and two teenagers, but they have not been positively identified, Hillsborough County Sheriff's Colonel Donna Lusczynski said. She described the fire as “unusual” and said there were “various fireworks” throughout the Tampa Bay-area home.

Two of the bodies appeared to have “upper-body trauma”, but she didn't indicate which ones or give any more details. She said no weapons had been found.

Former tennis star James Blake had been renting the home to the family for the past two years, Lusczynski said. He was not there at the time of the fire.

The home was in an upscale neighbourhood where many sports stars and executives live.

Blake bought the home in 2005 for $1.5 million, according to Hillsborough County property records. It had five bedrooms and five bathrooms. Video of the fire showed it totally engulfed in flames.

Lusczynski said the two teenagers were found in their respective bedrooms and the two adults were found in their bedroom.

Blake, 34, was ranked fourth on the ATP world tour in 2006 before he retired last year. - Sapa-AP