Three of the car's four inside door handles were missing, which may have prevented Brandon Lee Viera from getting out, fire Capt. Doug Mummert said.

"The child had been playing outside and reportedly had not been seen for approximately 30 minutes or more before being found by a neighbor," Mummert said.

Paramedics who arrived in the 7700 block of South Valencia Drive about 12:15 p.m. found the boy unconscious on the passenger seat and tried in vain to revive him.

"The child's temperature measured 108 degrees Fahrenheit, which is approximately 10 degrees above normal," Mummert said.

Temperatures inside the car, which was parked in front of the Medina home, were estimated at 150 degrees.

Brandon died less than an hour later at Good Samaritan Regional Medical Center.

Mummert said the boy, who was under the supervision of his 13- and 15-year old sisters, had crossed the street to play at a neighbor's house.

The girls began looking for him 15 minutes later, with a neighbor's help. They eventually looked in the car and found Brandon unresponsive.

The tragedy was the city's first heat-related death this year, Mummert said.

"It's very rare that a child crawls into a vehicle and can't get out, because normally, they get out on their own," he said.

"What we have more often is a small toddler or baby that is forgotten inside the back of the car."