Park City ? A 22-month-old Sedgwick County girl died after being left all day in a sport utility vehicle her family had agreed to loan to relatives, authorities said.

Alyssa Dillman, of Valley Center, and her 4-year-old brother were dropped off in a GMC Suburban by the children’s father around 9:30 a.m. Monday at an uncle’s house. Dillman was not found until 5:30 p.m., when her mother returned to pick the children up.

Emergency crews arrived after the family called 911, but Alyssa was pronounced dead at Via Christi Regional Medical Center-St. Francis. The toddler had been doused with water to cool her down and it was unclear whether she died while in the vehicle or at the hospital, Sedgwick County Sheriff’s Maj. Jackie Stuart said.

“I think it’s an unfortunate situation,” Stuart said. “It’s a horrible tragedy.”

The high temperature in Wichita, the county seat of Sedgwick County, was 109 degrees around 4 p.m., the highest reading this year, said Mike Kreyenhagen of the National Weather Service in Wichita. After caring for the toddler, authorities measured the temperature inside the vehicle at 142 degrees, even after the Suburban had been open for a short time.

The family dropped off the Suburban and drove away in another vehicle without notifying the uncle, Stuart said. Stuart said the girl’s brother left the car and went inside his uncle’s mobile home. When asked where his sister was, the boy said she was “sleeping,” Stuart said. Stuart said the family apparently assumed the girl had stayed at home. Although the uncle provided the children’s day care regularly, both children did not always come to his home, Stuart said.

An autopsy was planned Tuesday, but Stuart said authorities were fairly certain about the expected results.

“It was obvious that the baby had been left in there the entire day,” Stuart said.

Stuart said the family had been cooperative in the investigation and no charges had been filed Tuesday, pending a review by the district attorney’s office.

Law enforcement investigators film a GMC Suburban, left, in Park City, where a 22-month-old girl died after being left in the vehicle for eight hours. Temperatures reached 109 degrees Monday while the girl was in the vehicle. The temperature inside the Suburban was measured at 142 degrees after the girl was discovered.