Autopsy results show Wis. toddler found in trunk likely died from hyperthermia due to heat

BALSAM LAKE, Wis. — A Wisconsin toddler found in the trunk of a car likely died of hyperthermia due to the heat, authorities said Friday.

The Polk County Sheriff's Department released a brief statement summarizing preliminary findings from an autopsy on 2-year-old Isaiah Theis. The examination showed the boy was normally developed and well-nourished. It revealed no sign of any diseases, traumatic injuries or broken bones.

The statement listed the cause of death as probable hyperthermia, a condition where body temperature spikes. The manner of death is still under investigation. Toxicology tests are still pending.

Sheriff Peter Johnson called the boy's death "a terrible" conclusion to the long search for him, WCCO-AM of Minneapolis reported.

"Obviously this is pretty much the worst ending we could have come to," Johnson said Friday at the end of a news conference, where he read a statement about the autopsy but did not take questions. "The only thing worse would have been if we would have never found him."

The boy's mother told investigators he disappeared Tuesday evening while playing with his 7-year-old brother at their home near Centuria, Wis., about 60 miles northeast of St. Paul, Minn.

The sheriff's department launched an exhaustive all-day search Wednesday amid blistering heat. A deputy finally found the boy's body late Wednesday evening in the trunk of a locked car parked outside the boy's home. His father runs an auto shop on the property, and the discovery was made when the car's owner came to retrieve it.

Chief Deputy Steve Moe told reporters at a news conference Thursday that, in hindsight, he wished they had. But he said searchers were operating under the assumptions that Isaiah had wandered off, which he had a tendency to do, and that all the cars were locked so he couldn't get in them. He said deputies didn't have access to the keys, and that he's not certain whether the keys were on the property.

"Would we liked to have forced entry to the car? Yeah, from my personal perspective," Moe said.

He declined to speculate on how the boy ended up in the trunk and wouldn't say whether investigators consider his death an accident or the result of foul play.

Isaiah's maternal grandfather, Paul Krey, told KARE-TV that the car belonged to one of his son-in-law's customers. Krey said the car was parked there and waiting to be fixed. All the Theis children were comfortable hanging around the shop and spent plenty of time around the vehicles while their father worked, the grandfather said.

Krey did not immediately return a phone message Friday that The Associated Press left at a number believed to be to his residence in St. Paul. The voice mailbox for the boy's parents, Justin and Shawn Theis, was full on Friday and would not take any more messages.

Debbra White, 51, of Milltown, Wis., left a teddy bear and a wind chime at a makeshift memorial near the scene. White told the Star Tribune of Minneapolis that she lost her 8-year-old son more than 20 years ago when he drowned in the St. Croix River.