The Cumberland County Sheriff's Department said today its investigation into Friday night's drowning of a 5-year-old boy in Sebago Lake is still not finished.

Sheriff Mark Dion said deputies returned today to Northwest River Road in Sebago where the boy lived to re-interview the boy's foster father.

"The mechanics of how this drowning occurred are still not clear to us yet," Dion said.

Dion and Capt. Don Goulet said the foster father has a physical handicap, having suffered a brain injury during a pool accident. He relies on a cane to walk, Goulet said.

Goulet said the foster father had been swimming with the child prior to the accident. There are no witnesses.

Authorities said they are not prepared to identify the boy or the foster father until their investigation is complete. The results from an autopsy on the child are also being withheld.

State police have been called in to consult on the case, but Dion and Goulet said that should not be construed to mean that the case is being treated as a criminal matter.