A man drowned in the St. Croix River on Sunday after diving off a pontoon boat, according to the Pierce County Sheriff's Office.

Keith Taylor, 66, of Cottage Grove was with friends and family on a boat parked onshore at Kinnickinnic State Park, across the river from Afton, Minn. He dove off the boat's diving board and did not immediately resurface, witnesses said. Friends and family pulled him from the water and started CPR. Authorities were notified at about 1:24 p.m. First responders arrived and continued CPR until Taylor was pronounced dead.

The Pierce County Sheriff's Office was assisted by Allina EMS, the Prescott Police Department, the Wisconsin Department of Natural Resources, the River Falls Fire Department and Life Link III.