LOUISVILLE, Ky. (AP) — Crews resumed searching in Monday for three people missing after their pontoon boat hit a barge and capsized in the Ohio River in Kentucky, leaving two others dead, a fire chief said.

Louisville Fire Chief Greg Frederick said the search has turned into more of a recovery effort given the amount of time since the boat capsized.

"We're not ruling out a remote chance, but for the most part, we're in recovery mode," he said.

Nine people were aboard the boat when it capsized Saturday night. Four people, including three children wearing life jackets, were rescued. Frederick said one of those still missing is a child.

Jefferson County deputy coroner Jim Wesley told The Courier-Journal (http://cjky.it/1CkxAY9) that the two who died were 52-year-old Donald Swinney and 14-year-old Mark Swinney Jr. Wesley said the cause of death for both was drowning. He said the victims were related, but their relationship was unclear.

Frederick said officials expect the search effort to be challenging because of treacherous river conditions, including swift currents carrying lots of debris. He said crews would use sonar and search surface locations because river conditions are too dangerous to send in divers.

"You've got entire trees floating at a pretty good speed down that river, and if that were to hit a diver or entrap them, we would lose them, so we're very cautious about putting divers in in these conditions," he said.

The barge that the pontoon boat hit was at a construction site about a mile upstream from the Clark Memorial Bridge.