The bodies of a reported family of four were found following a fire at a Florida property owned by former tennis player James Blake.

The authorities have confirmed that the blaze was a deliberate act which killed four people, believed to be two adults and two teenagers.

Hillsborough County Sheriff Col. Donna Lusczynski told reporters: "We have also confirmed that the fire was started intentionally by an unknown accelerant."

Lusczynski, who revealed that two of the bodies had upper body trauma, claimed that two of the individuals were found in one bedroom, while the other two were discovered in separate bedrooms.

The authorities have confirmed that Blake was renting out the property and was not at the home at the time of the fire, which the police were alerted to at 5.45am on Wednesday morning.

It has also been confirmed that small commercial-type fireworks were found in the property.