ONEONTA, Ala. (AP) — An Alabama man is facing a reckless manslaughter charge after his 2-year-old grandson died when he was left in a hot vehicle for seven hours, authorities said Wednesday.

Two-year-old Ian Wiesman died Tuesday after being left inside a truck for seven hours as late summer temperatures hovered around 90 degrees (32 Celsius), authorities said. William “Bill” Wiesman, 56, is being charged with reckless manslaughter and criminally negligent homicide for the death of his grandson, authorities said.

Bill Wiesman told authorities he thought he had dropped his grandson at daycare that morning, and did not notice the child still strapped in a car seat as he went to work. Blount County District Attorney Pamela Casey said Wiesman returned to the truck three times that day but told authorities he did not notice the child.

The toddler, who was strapped in a forward-facing car seat behind the driver’s seat, was discovered when Weisman drove to the daycare around 3 p.m. Tuesday, authorities said.

“He went back to the daycare thinking he had left the child there but had been in the vehicle three times that day from the time he picked the child up until the time he returned to the daycare,” Casey said.

The district attorney announced the arrest warrants during a news conference. The charges indicate authorities believe the child’s death was unintentional. “These are not intentional acts. These are negligent acts and or reckless acts,” Casey said of the charges. She said the investigation is ongoing.

It is unclear if Wiesman has an attorney who could speak on his behalf.

Casey, the mother of two young children, fought back tears when asked about the emotions surrounding the child’s death. “It’s awful. My heart breaks for this family,” she said.

At least 28 children left inside vehicles have died this year in the U.S., including six this month, according to a website that tracks such cases, kidsandcars.org.

“I believe everyone I saw on the scene has children, so it’s extremely difficult to be involved in something like that,” Oneonta Police Chief Charles Clifton told reporters during a briefing.