The western Wisconsin 2-year-old whose body was found in the trunk of a vehicle after a massive day-long search died of "probable hyperthermia," meaning his death was likely heat-related, according to preliminary autopsy results released Friday afternoon, FOX 9 reports.
Hyperthermia is "abnormally high body temperature caused by a failure of the heat-regulating mechanisms of the body to deal with the heat coming from the environment" – the body can't cool itself, according to the National Institutes of Health.
The autopsy indicates the toddler did not suffocate in the car trunk, nor did he suffer traumatic injuries, FOX reported. Medical examiners say he was an otherwise healthy, well-developed boy.
The finding was made by the Midwest Medical Examiner’s Office in Anoka County and announced by Polk County Sheriff Peter Johnson, the Star Tribune reported.
Investigators are speculating on how the boy got into the trunk of the locked car.
"I know that there's strong interest in what caused it and what things led to the boy getting in that car," Polk County Chief Deputy Steve Moe said, FOX reported. "It's just too early."
The boy's body was discovered in the trunk of a Chevrolet Impala around 10:15 p.m. Wednesday, after as many as 2,400 volunteers joined the search around his family's rural property near Centuria, Wis., the Star Tribune noted. His parents had said he was playing with his 7-year-old brother Tuesday night and wandered off.
An emotional candlelight vigil was held for the boy in Centuria on Thursday night.