A boy and a girl, 18-month-old twins, accidentally drowned in a pool at their family home in Oklahoma after their Alzheimer’s-inflicted great-grandmother left a back door open.

On Thursday, March 16, at around 10:45 a.m., the twin’s mother discovered her babies at the bottom of the pool, and they were pronounced dead at 1 p.m.

Locklyn and Loreli had lost consciousness by the time their mother, Jenny Callazzo, discovered them at the bottom of their pool.

As first responders from the Oklahoma City Fire Department arrived, they saw Callazzo, 37, administering CPR to the twins and desperately attempting to save them.

Callazzo is a stay-at-home mom who runs an online boutique store and lives in Cobblestone, Oklahoma, with her husband, marketing executive Sonny Callazzo, 42, her six children, and her grandmother. 

Aerial footage of the house shows a pool with algae-filled, greenish water.

The death of the twins has been investigated, but police say it does not appear to have been intentional.

On the way to Baptist Hospital, paramedics continued to perform CPR on the toddlers, who were pronounced dead on arrival.

The Oklahoma City Fire Department said in a statement that they didn’t know how long the babies had been in the pool.