MALVERN, Pa. (AP) — The Irish immigrants building a stretch of railroad near Philadelphia in 1832 had been in the U.S. only a few weeks when they died — ostensibly of cholera — and were unceremoniously dumped in a mass grave. Their families never knew what happened to them.

Nearly 180 years later, local researchers say they have a clearer picture of the men's fate. But their massive effort to unearth, identify and properly re-inter the workers' remains will not be realized; the grave is inaccessible, they say, and will remain undisturbed.

Still, enough evidence exists to prove that some laborers were victims of murder, not disease, according to historians Frank and Bill Watson. And while it's likely the unrecovered bones may have been too degraded to yield testable DNA, one set of remains found apart from the main ossuary might still be positively identified and returned to Ireland.

"Since the beginning, we have seen it as our job to get their story out of folklore and into actual history, and we hope we have done that," Bill Watson said....