Officials are investigating the death of a two-year-old boy who walked out of a home and fell into a pool in Waldorf Monday morning.

The Charles County Sheriff’s Office said the incident happened shortly before 10 a.m. in the 3600 block of Yorktown Drive.

The home is the site of a daycare.

The provider—who is licensed—was watching three children. She opened the back door to let a dog out, closed it and walked away from the room for a few minutes, the sheriff’s office said. When she returned, the door was open and a child was missing.

The woman immediately went outside and found the toddler in the pool, detectives said.

Officers arrived to find the child on a rear deck not breathing. The daycare provider had started CPR. Officers took over and continued until EMS arrived.

The child was taken to Southern Maryland Hospital and was pronounced dead a short time later.

The investigation is still ongoing.