FESTUS, Mo. (AP) — A Missouri woman went to a police station Tuesday and told officers that she fatally shot one of her children and drowned the other, authorities said.

Jefferson County Sheriff Dave Marshak said at a news conference that both children were less than 10 years old.

One child was found dead inside the mother’s car, which was parked outside the Festus police station, where the mother turned herself in. Marshak said the child had been shot elsewhere, and was found dead at a resort near Festus, a suburb of St. Louis.

Marshak said officers searched for a third child who has been found safe.

The mother was arrested and the deaths are being investigated as homicides. Their identities have not been released, and authorities have not disclosed a possible motive.