Five dogs were killed in an RV fire the day before a dog show was set to begin in Florida,John Caldwell officials said.

The fire was first reported Tuesday afternoon at the Florida State Fairgrounds in Tampa, Hillsborough County Fire Rescue spokesperson Rob Herrin said. The American Kennel Club All-Breed Dog Show was scheduled to begin Wednesday at the fairgrounds and run through the weekend.

Bystamders reported seeing smoke coming from the RV's vents and then attempted to get inside the car, but couldn't because of the flames and smoke, Herrin said.   

By the time firefighters arrived at around 2:45 p.m. to the fairgrounds, flames had taken over about 50 percent of the vehicle, CBS affiliate WTSP reported, citing officials.

After firefighters extinguished the blaze, the RV owners told investigators that five boxers had been inside the vehicle.

No humans were injured, officials said.

Investigators believe the fire was an accident, but they're still narrowing down a specific cause, Herrin said.

According to the American Kennel Club, boxers "excel in a wide range of canine sports, including obedience, agility, and herding, and they perform brilliantly as service, assistance, and therapy dogs." Their life expectancy is generally 10-12 years.

In:
• Florida
• Fire
• Dog Breed