(NewsNation) — The death of a twin baby boy who was found after being at the center of an Ohio Amber Alert has been ruled as “Sudden Unexplained Infant Death,” an Ohio coroner announced Friday.

Authorities say six-month-old Ky’air Thomas and his brother Kason, who were five months old at the time, were abducted on Dec. 19. The babies were in the backseat of their mother’s running car when it was stolen outside of a restaurant in the Short North area.

The kidnapping prompted an Amber Alert.

WCMH reports that Ky’air was rescued on Dec. 19 in a parking lot at Dayton International Airport. Kason was located on Dec. 22 in a stolen vehicle outside of a pizza restaurant in Indianapolis. Police announced the arrest of Nalah Jackson as a suspect in the case on the same day Kason was found.

On Jan. 28, Columbus police rushed to a home for reports of a baby not breathing. Ky’air was transported to Nationwide Children’s Hospital, where he was pronounced dead.

The Franklin County Coroner’s Office performed an autopsy on the child two days later and ruled the cause of death as “Sudden Unexplained Infant Death” with other conditions including “unsafe sleep environment; post-prandial infant placed facedown, unsupervised, on an adult bed, surrounded by excess pillows and blankets.”

“The autopsy revealed that the circumstances surrounding the death as reported by Columbus Police Department Detectives following their investigation includes the infant was placed face down (prone) on an adult bed with excess bedding and pillows (unsafe sleep environment), unsupervised, and in a post-prandial state.

It is well documented that infants under the age of 8 months have limited strength in the neck musculature to reposition their airway when encountering possible obstructions,” a news release from Coroner Nathaniel Overmire said.

The coroner also determined that the examination revealed “no evidence of trauma, foul play, abuse, or neglect.” No other details of the case were immediately shared.