KANSAS CITY, Mo. (AP) — Authorities say the deaths of 3-year-old twins in a Missouri pond were apparently a “tragic accident.”

The Kansas City Star reports that Platte County Undersheriff Maj. Erik Holland says Arrabelle and Elijah Wagner were found Monday after their father awoke and realized they were missing. The pond was behind their home near Edgerton, about 30 miles north of Kansas City.

Arrabelle was found alive in the pond, and responders searched the house for Elijah thinking he may have gone inside to get help. But divers eventually found him in the pond near a covered dock. He was pronounced dead at the scene. Arrabelle died later at a hospital.

Holland says the deaths would be “thoroughly” investigated although there was nothing pointing to “anything other than a tragic accident.”