VIDEO - Irish Ambassador visits Duffy's Cut

The mystery of Duffy’s Cut, how 57 Irish immigrants died and were anonymously buried in the summer of 1832, could be coming to a close. Two new skulls unearthed show evidence of violence and possibly a bullet hole.

In the summer of 1832 a group of 57 Irish immigrants came to the area west of Philadelphia to work on the construction of the railway line. Within six weeks the men, mainly from Donegal, Tyrone and Derry, were all dead and anonymously buried in a mass grave outside the town of Malvern.

For some time it was thought that the mass grave was due to an outbreak of a dangerous disease such as cholera and this was simply a way of dealing with infection. However, the new evidence paints a different picture. While the two skulls found more recently show signs of violence and a bullet hole the previous skulls unearthed also showed trauma.

These grizzly finds confirm what the two leading historians on the archaeological dig feared. “This was much more than a cholera epidemic”, said William Watson.

Chairman of the history department at Immaculata University, William Watson and his twin brother, Frank, have been working on this archaeological mystery for almost a decade.

Since 2009 the Watson brothers have uncovered seven sets of remains. One of the victims has been identified, pending DNA tests.

For seven years before the brothers found nothing at the site and the hypothesized had been that the group of men had died of cholera. The disease was rampant at the time and the mortality rate was between 40 and 60 percent.

They theorized that some might have been killed by vigilantes due to the anti-Irish sentiment in the 19th century America, because of tensions between the poor transient workers and the affluent residents or an intense fear of cholera. It could have been a combination of all three.

Now that the Watson brothers have four skulls all with evidence of trauma they show that the men were struck in the head. Janet Monge, an anthropologist working on the site, says that at least one of the men was shot.

Monge said “I don't think we need to be so hesitant in coming to the conclusion now that violence was the cause of death and not cholera, although these men might have had cholera in addition."

“They do have indications on their skeletons that life was not a bowl of cherries,” said Monge who is the keeper of collections at the University of Pennsylvania Museum of Archaeology and Anthropology.

The bones show that the laborers were muscular despite having poor diets and their teeth show that they were not wealth enough to have afforded sugary sweets.

They also found coffin nails among the corpse’s bones which show that some of the bodies had received some kind of formal burial.

The Watsons discovered the mass grave through the personal papers of their late grandfather who had worked on the rails long after the 57 men were killed. The projects name comes from the name of the man who hired the group of Irish men, Philip Duffy, and the part of the railroad that the men were hired to build, the cut.

When the immigrants died, or were killed, in 1832, Duffy ordered the shantytown, where they had lived, to be burnt and their bodies buried in the railroad fill. The Watsons say the men’s families were never told of their deaths.

Four months before their deaths a passenger ship, the John Stamp, arrived from Ireland. The passenger list offers the possible identity of 15 workers from Donegal, Tyrone and Derry.

The Watsons believe that they have been able to identify 18-year-old John Ruddy as one of the bodies found. They compared his bone size to the ship’s manifest and also found a section of teeth with a rare genetic anomaly which they believe matched with an anomaly shared by some Ruddy family members in Ireland. The DNA results should be returned in six months.

The 47-year-old twins both have doctorates in history but have nothing more that introductory biology.

“It has been indeed a crash course…and it's been fascinating," said Frank.

Monge said "They're as professional a team as anyone I've seen out there on a site."

As well as being a way of documenting the early 19th century attitudes to industry, immigration and disease in Pennsylvania the brother’s ultimate goal is to find all of the men’s remains and property and inter them properly, either in the U.S. or Ireland.

We see this more as a recovery mission," William said. "Get them out of this ignominious burial place."

VIDEO - Irish Ambassador visits Duffy's Cut