Authorities on Sunday identified a young girl and her father who drowned in a swimming pool a day earlier at a backyard birthday party in Waldorf.

Christian Omofolawe Agboola, 7, who was a guest at the party along with her father, jumped into the deep end of the uncovered in-ground pool at a residence in the 1200 block of Jefferson Lane. Her father, Haffis Olanrewaju Agboola, 44, of Hyattsville, jumped in to try to save her, Charles County Sheriff’s Office spokesperson Diane Richardson said.

She said neither knew how to swim.

A 17-year-old boy who was unrelated to the two jumped in and tried to help, she said. The boy, who was not identified, was flown to Children’s National Hospital, where authorities said he was in critical condition.

Charles County officials received calls about the incident just before 6 p.m. Saturday. All three were removed from the water. Then four firefighters and an officer performed CPR.

“Between trying to rescue them and struggling, everyone took in too much water,” Richardson said. “I just think everything was chaotic.”

The victims were taken to the University of Maryland Charles Regional Medical Center, where the father and daughter died, Richardson said. Two firefighters injured during the rescue were treated at the hospital and released.

The birthday party was for an adolescent, Richardson said, adding that the water in the pool was about eight or nine feet deep.