On the evening of September 21, 1924, the cargo steamship SS Clifton met its end in Lake Huron while carrying a 2200-ton load of crushed stone from Sturgeon Bay, Wisconsin to Detroit. The vessel was likely caused to sink by a gale, and the disaster resulted in the deaths of 25 crew members. Bits of wreckage were later found, but the freighter’s resting place ultimately remained a mystery. Now, more than 90 years later, the Associated Press reports that the SS Clifton’s location at the bottom of the Great Lake has been confirmed.

Scuba diver David Trotter—who’s reportedly located more than 90 Great Lakes shipwrecks—discovered the SS Clifton in September 2016, following a 30-year search. He waited to publicly share the news until his company, Undersea Research Associates, was able to investigate and document the steamship's remains last summer.

Trotter had spent decades searching for the SS Clifton, but finding it was ultimately a matter of serendipity, he says. In June 2016, Trotter and his team were surveying two wrecks—the schooners Venus and Minnedosa, which sank in 1887 and 1905, respectively—when they spotted yet another submerged ship. They logged its coordinates, but only managed to get a closer look several months later, in September 2016, during a quick dive trip.

GoPro footage confirmed that the ship in question was a whaleback steamer, a unique type of 19th century cargo steamship with low, rounded hulls, decks, and deckhouses, which were designed to cut down on water and wind resistance. “The Clifton was the only whaleback ship left in Lake Huron that hadn’t already been found,” Trotter said, according to WZZM-TV. “There was no question we had found the Clifton.”

The USS Clifton sits on its side, around 100 miles south of where some shipwreck hunters initially believed it had sunk. Its bow is shattered, likely from the collision with the lake’s bottom, while the stern, inside paneling, and architecture remain well-preserved. Divers also spotted an unopened suitcase, and signage inside the ship.

So far, there isn't any clear mechanical evidence as to why the USS Clifton sank, but Trotter's team did find “that the self-unloading mechanism was still in position,” he says. This was “an interesting discovery because we now realize that the unloading mechanism didn’t break free, causing the Clifton to have instability, resulting in her sinking.”

Trotter hopes to explore the USS Clifton’s engine room and cabins, and to bring the suitcase ashore to examine its contents. Until then, he can remain satisfied that he’s finally solved a mystery that had eluded him for much of his career.

[h/t Associated Press]