A shipwreck researcher claims to have solved a mystery surrounding a tragic plane crash nearly 60 years ago.

Valerie van Heest says human remains from the June 1950 crash into Lake Michigan washed ashore and were buried in a mass grave.

She claims they were buried in a St. Joseph-area cemetery without the knowledge of the victims' families, and the grave never was marked.

Now, van Heest says a monument engraved with the victims' names will be unveiled at the cemetery a week from Saturday. She says families of 47 of the 58 victims have been notified about the find.

Northwest Airlines Flight 2501 was en route from New York to Minneapolis when it went down offshore from South Haven.