Researchers may have discovered a mass grave for nearly five dozen 19th century Irish immigrants who died of cholera weeks after coming to Pennsylvania to build a railroad.

Historians at Immaculata University have known for years about the 57 immigrants who died in August 1832, but could not find the actual grave. Human bones discovered last week near the suburban Philadelphia university may at last reveal their final resting place -- and possibly allow researchers to identify the remains and repatriate them.

"We feel a kinship with these men,'' said Immaculata history professor William Watson. "Righting an injustice has led us to this point.''

The woodsy site where the bones were found is known as "Duffy's Cut.'' It is named after Philip Duffy, the man who hired the immigrants from Donegal, Tyrone and Derry to help build the Philadelphia and Columbia Railroad.

Years of combing the several acres of rough terrain that comprise Duffy's Cut had so far yielded only artifacts such as pipes, buttons and forks. But on Friday, researchers using ground-penetrating radar were able to unearth pieces of two skulls along with dozens of other bone fragments and teeth. The findings were announced Tuesday.

Research led Watson to conclude many of the Irish workers died of cholera, an acute intestinal infection caused by contaminated food or water that typical had a mortality rate of 40 percent to 60 percent.

Watson believes some of the workers may have been murdered because of their illness or ethnicity.