ST. PAUL, Minn. (AP) — Scientists think they've solved the mystery of the Devil's Kettle waterfall at a state park in northeastern Minnesota.

The falls are on the Brule River at Judge C.R. Magney State Park near Grand Marais. The river splits at a rock outcropping. Visitors see how the east side falls 50 feet into a pool like other waterfalls. But the water on the west side plunges into a hole in the rock and vanishes.

The Department of Natural Resources said Tuesday that hydrologists believe that water re-enters the river from underground, not far downstream. They concluded that because the water volume flowing over the two falls is nearly identical to the flow below them, so the mystery water isn't flowing someplace else.

They plan more tests this fall to confirm their findings.