An initial investigation indicates the toddler’s father arrived home while she was asleep in the car, and he left her there with the vehicle running and the air conditioner on while he went inside his home, according to police in Marana, located just outside Tucson.

Her mother eventually arrived home, and shortly afterward the child was discovered unresponsive inside the car, which was no longer running and had the air conditioning off, police said. Someone called 911, and firefighters and Marana police arrived shortly after 4 p.m., police said.

The girl was left in the car for about 30 minutes to an hour before she was found, police told CNN affiliate KNXV.

Resuscitation efforts were done on the child and she was transported to a hospital, where she was pronounced dead, according to police.

Marana police detectives were granted a search warrant Tuesday night and an investigation into the death is ongoing, police said.

“We are doing our interviews with the dad, any witnesses, neighbors, to determine if the car was still running, if the AC was still operational,” Marana police Capt. Tim Brunenkant told CNN affiliate KPNX. “All we know is it was a hot car and the child was unresponsive, it was very hot, and it’s very tragic.”

Afternoon air temperatures in the Marana area on Tuesday ranged from 102 to 108 degrees, according to the National Weather Service. Much of the western and southern US has been experiencing a long-lasting heat wave that has led to numerous daily high temperature records and caused deaths.

In Omaha, Nebraska, police say they are investigating the death of a 5-year-old boy after they found the child Wednesday unresponsive inside of a vehicle. It appeared he had been left there for an extended period of time, police said. The area’s high temperature that day was 89 degrees, according to the National Weather Service.

Ten children have died as a result of being in a hot vehicle in the US this year, according to NoHeatStroke.org, a website that tracks hot car deaths and is run by a San Jose State University lecturer. Since 1998, 44 children have died from vehicular heatstroke in Arizona, according to the National Safety Council.

On average, 37 children under the age of 15 die each year from heatstroke after being left in a hot vehicle, the council says. In 2023, 29 child hot car deaths were reported in the US, according to the council. Since 1998, the highest annual number of children known to have died after being left in a hot vehicle was 53, recorded in both 2018 and 2019, according to the council.

A child’s body temperature rises three to five times faster than an adult’s, and children can die when their body temperature reaches 107 degrees, according to the National Highway Traffic Safety Administration. Of the pediatric heatstroke deaths reported from 1998 to 2023, about 52% happened because a caregiver forgot the child in a vehicle, according to NoHeatStroke.org, which cited media reports of the deaths.

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