Authorities are investigating the weekend death of a 42-year-old New Hope, Minn., man, who surfaced in distress during a shipwreck dive only to go underwater and later be located unresponsive on the bottom of Lake Superior.

Aaron Timmerman had been scuba diving with a group on the wreck of the barge Madeira - a popular diving site in the waters off Split Rock Lighthouse State Park. Witnesses saw Timmerman surface and call for help, but no one was able to get to him before he went under, said the Lake County Sheriff’s Office in a news release on Monday.

He was located on the bottom of the lake by two members of his group and brought to the surface. Authorities arrived to shore Saturday shortly after 1 p.m. to find other divers attempting lifesaving efforts.

The cause of death will be determined by the medical examiner, the Sheriff’s Office said.

Timmerman was pronounced dead at 2:10 p.m., in a landing zone at Gooseberry Falls State Park, where the Two Harbors Fire Department was maintaining a site for the Life Link helicopter. Life Link staff, in consultation with emergency room doctors, pronounced Timmerman dead at the scene, the Sheriff’s Office said.

The Lake County Rescue Squad, Lake County Ambulance and Minnesota Department of Natural Resources park rangers also responded to the scene.

The Madeira was one of 20 vessels damaged or wrecked in 1905 during the Mataafa Storm which is generally regarded as the worst in Lake Superior history. Split Rock Lighthouse was erected in 1910 within sight of the wreck, said a Minnesota Historical Society description of the wreck. The Madeira wreck featured a heroic rescue effort which saved nine members of the 10-person crew.