A 14-year-old Superior boy died overnight Thursday due to medical complications that arose from being underwater for "multiple minutes" before bystanders found him.

According to the St. Louis County Sheriff's Office, the boy, who was identified Thursday as David Beck, was swimming out to a diving dock about 75 yards offshore on Little Grand Lake near Sampo Beach Tuesday with several other boys shortly after 8 p.m. when he went under water and didn't reemerge. The other boys yelled for help and bystanders from the beach and nearby boats began diving to search for Beck.

The bystanders were able to find Beck at the bottom of the lake in about 12-15 feet of water. CPR and lifesaving efforts were taken immediately, the sheriff's office said.

Beck was transported to a hospital, where he was listed in critical condition late Tuesday night. His family informed the St. Louis County Sheriff's Office Thursday that he had died overnight. The family said they were extremely appreciative for all the work and effort put in by those involved during the incident, a news release said.