Updated

A 2-year-old Wisconsin boy whose body was found in the trunk of a car Wednesday night had the key to the vehicle with him, the family's pastor said Saturday.

Isaiah Theis had that key and several other sets of keys with him when his body was found by a deputy, the Rev. Rick Van Gundy told The Associated Press. Van Gundy said he got the information from the Theis family but declined to be more specific, because of the sensitivity of the situation.

"This is breaking the heart of somebody who has a broken heart," said Van Gundy, pastor of St. Peter's Community Church in Dresser. "It's that much of a devastation to them that you can't even put a word to it."

The deputy found the boy in the trunk of a customer's car on his parents' property near Centuria, where the boy's father runs an auto repair business.

The child’s death was likely heat-related, according to preliminary autopsy results released Friday afternoon by the Anoka County medical examiner. The cause of death was listed as "probable hyperthermia" while the manner of death is still under investigation, MyFoxTwinCities.com reported. The autopsy also found that Isaiah was an otherwise healthy, normally-developed and well-nourished boy.

Polk County investigators have not yet said how Isaiah, who disappeared Tuesday night, got in the trunk. Sheriff Peter Johnson did not immediately return a phone call from the AP on Saturday.

The news about the keys was first reported Friday night by KSTP-TV. Van Gundy told the station he had personally shined a flashlight inside the car and looked under it when he joined the search Tuesday night, but that it never crossed anybody's mind to unlock the trunk.

Officials with the sheriff's department have made similar statements. Investigators said they presumed Isaiah had wandered off while playing with his brother Tuesday night because he had a tendency to do that.

About 2,450 civilian volunteers helped search the fields and woods surrounding the family's home, about 60 miles northeast of St. Paul, Minn., throughout the day Wednesday. But nobody looked into the trunk until the car's owner came to retrieve it Wednesday night.

Van Gundy said he was not surprised that Isaiah might have been able to use the keys to get into the trunk.

"He's an exceptionally smart little boy," he said, adding that he would often watch his father repairing cars and had picked up his father's mechanical aptitude. "If he saw you once he could emulate it, he could copy it."

The Theis family is still hurting deeply, Van Gundy said, describing them as "emotionally and physically tired, soul-weary but blessed."

According to MyFoxTwinCities.com, both parents have taken polygraph tests as investigators try to determine what happened.

Isaiah's funeral will be held in the coming week, but details were not settled, he said.

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The Associated Press also contributed to this report.