In June 1950, a four-engine, propeller-driven passenger plane headed from LaGuardia Airport in New York to Minneapolis encountered a violent storm over Lake Michigan and crashed into the turbulent waters below.

“If all aboard are lost, the crash will be the most disastrous in the history of American commercial aviation,” an article on the front page of The New York Times on June 25 reported about Northwest Orient Airlines Flight 2501. The search turned up no survivors and no plane, only small pieces of the wreck. All 58 people on board were declared dead.

The few human remains that the Coast Guard skimmed off the lake’s surface were buried in an unmarked mass grave. Newspapers were quickly distracted by the beginning of the Korean War.

Until a team led by local explorers set out in 2004 to find the plane, the mystery of Flight 2501 was little more than fodder for conspiracy theorists.

But more than 20 years later, that search has been called off. While it turned up no physical remains, explorers say, the effort revived the memory of the crash and honored the victims.

On Tuesday, the 75th anniversary of the discovery of the crash, Valerie van Heest, a local maritime history enthusiast who helped revive the search, told surviving family members of the victims that, after scanning the last of the 700-square-mile section of Lake Michigan where researchers suspected the wreckage had settled, she had determined that the plane had shattered upon piercing the surface of the lake and that time had buried the remnants too deep to detect.