BLACKFOOT, Idaho (AP) — Police are investigating after the body of a baby girl was found at a southeastern Idaho hospital in a box meant for people to anonymously give up a newborn, officials said Monday.

Police officers in Blackfoot, Idaho, about 250 miles (400 kilometers) east of Boise, responded Oct. 13 to a report of a deceased infant left in the Safe Haven Baby Box at Grove Creek Medical Center, news outlets reported.

Monica Kelsey, the founder of Safe Haven Baby Boxes, said in a social media post Monday that hospital staff responded within one minute to an alarm indicating a baby was in the box, which was installed earlier this year. The staff quickly realized that the infant had died before being placed inside.

“We are heartbroken," Kelsey said. “Anonymity is only allowed when an infant is safely surrendered completely unharmed.”

Idaho law only allows for the surrender of an infant who is unharmed and healthy.

The organization and hospital staff are working with police investigators, officials said. The baby had been wrapped in a blanket, and the placenta was still attached, Kelsey said.

Grove Creek Medical Center officials said in a social media post Monday that staff members “gave their all in a heartbreaking situation.”

Kelsey, who herself was abandoned after birth in 1973, launched Safe Haven Baby Boxes in Indiana in 2016. The boxes equipped at fire departments and hospitals are meant to provide a safe and anonymous way to surrender a newborn.

The medical-grade boxes are installed in the exterior wall of the building. An exterior door automatically locks when a newborn is placed inside, and a medical staff member opens an interior door to secure the baby.

Boxes are available in more than a dozen states. Since 2017, 52 infants have been surrendered at the organization's baby box locations, Kelsey said.

She said Safe Haven Baby Boxes will continue to educate people about how the program works.