Minnesota authorities have identified a 9-year-old Wisconsin boy who was fatally injured by a lightning strike on a Lake Superior beach.

The St. Louis County Sheriff's Office says Luke Voigt, of Iron River, Wis., was flown to a Duluth hospital after the lightning strike on Saturday, but was pronounced dead after efforts to revive him failed.

The sheriff's office also says his 7-year-old brother, Daniel Voigt, was on shore during the lightning strike and was not injured.

The boys were among eight family members and friends who were on a sailboat that took refuge from a rapidly approaching thunderstorm on the end of Minnesota Point, near the Superior Entry to the Duluth-Superior harbor.

Four others in the group were taken to Duluth hospitals with what authorities described as severe but not life-threatening injuries.