BELGRADE — The Maine Warden’s Service is investigating what caused a 25-foot-long pontoon party boat to crash on Great Pond late Saturday night

Deborah Turcotte, spokeswoman for the Maine Department of Inland Fisheries and Wildlife, said the boat hit a rock pile on the southern end of Oak Island around 10:30 p.m.

Three of the five people on board the boat, which is owned by John Jabar, 50, of Belgrade, were injured.

Jabar was injured but refused medical treatment. Two passengers were treated and released from Inland Hospital in Waterville, Turcotte said.