Three people on a northern Minnesota lake were thrown from a boat in an incident that left an Eden Prairie swim coach dead and the other two alive thanks to the rescue efforts of nearby fishermen, authorities said Sunday.

Jailed on suspicion of boating while intoxicated was Matthew A. Kinghorn, who turns 45 on Monday, of Minnetonka. Kinghorn was operating the boat late Saturday afternoon on Cass Lake, according to the Beltrami County Sheriff’s Office.

The woman was identified as Brenda L. Larson, 50, of Eden Prairie. Authorities have not identified a 4-year-old who was aboard or revealed the child’s relationship to either adult.

Larson was a swim coach for Eden Prairie-based Team Foxjet, which registers more than 400 youngsters a year. Friends and family described Larson as an outgoing person who enjoyed spending time with kids and had a passion for swimming.

“She loved teaching and connecting with the little ones,” said Foxjet head coach Ann Urschel.

Larson trained children 8 years old and younger, Urschel said. Just last week, Larson baked cookies for the entire team, she said.

“Everyone is quite shocked,” Urschel said, about the news of Larson’s death.

Larson’s brother Pete Hulke said that his sister, who has two sons, was the youngest of five children and grew up in Merrill, Wis. When Larson was a child, it was discovered that she suffered from a severe blood infection that caused her to have bone growth difficulties. After being hospitalized, Larson was able to participate in her high school swim team.

“That was a sport, even with her disability, that she could participate in,” Hulke said. He added, “Swimming was one thing she felt really successful at.”

Hulke did not have any details about what happened Saturday.

According to the Sheriff’s Office:

About 4:15 p.m., sheriff’s deputies responded to a 911 call of a woman who was spotted unresponsive in the water on Cass Lake.

While underway, Larson, Kinghorn and the child were thrown from the boat. The driver and the 4-year-old were rescued by fishermen who were passing by.

A short time later, Larson was recovered from the water, unresponsive and not breathing. She was brought to shore by rescuers and taken by ambulance to the Cass Lake Hospital, where she was pronounced dead.