SALEM — On a June day in 1975, lobsterman Michael Zdanowicz Sr. was pulling up a trawl line in Salem Harbor when he stumbled across something unexpected.
The artifacts he found that day touched off a 35-year quest for treasure buried centuries ago when a ship called Margaret smashed into a shoal and sank with her cargo of porcelain from China, Spanish silver and Dutch gold.
The Margaret sank in 1797, and since then, treasure hunters have hoped to find her and the riches onboard, likely worth millions.
Along the way, Zdanowicz, of Peabody, and his family found others who shared their dream. Two of them were Joseph Dietlin and Duane Rine.
In 2000, the Zdanowiczes agreed to team up with Dietlin and Rine, who, they say, told them that their business, which they called "North Atlantic Treasure Salvage Company," could help out with their expertise in marine salvage.
Instead, the Zdanowiczes contend, Dietlin, as well as Rine (who died last year in a diving accident), helped themselves, accepting money and equipment from the Zdanowiczes, but then getting a permit to explore the site under their own names.
Yesterday, they filed a lawsuit against Dietlin and the estate of Rine, claiming that the permit from the Massachusetts Board of Underwater Archaeological Resources was obtained fraudulently and that Dietlin and Rine acted in bad faith, cutting them out of the loop.
The suit, filed in Salem Superior Court by Braintree attorney Charles Monahan, seeks a court order that bars Dietlin and any of Rine's heirs from taking anything from the site, or from disturbing it in any way.
The suit also asks that Dietlin be required to sign over all rights to explore the site, granted in the state permit, and to return any artifacts or other items recovered from the site or given to them by the Zdanowiczes.