McParlan set out on his mission Monday, October 27, 1873, in the disguise of a vagabond Irishman seeking employment in the mines, and as a criminal who was seeking refuge from crimes committed in the vicinity of Buffalo, N. Y.
He assumed the name of James McKenna, and as such won his way into the confidence of the Mollies, joined their organization and became known as the most desperate Mollie in all the anthracite region.
Many others were murdered after McParlan arrived in the region. He prevented murder when it was possible to do so. He warned those who were to be victims through Mr. Franklin, superintendent of the Philadelphia and Reading Coal Company, with whom he kept in daily contact by clever correspondence.
Up to the hour that James McParlan arrived in Schuylkill County, no information had been obtained concerning the identity of those who murdered Littlehales, nor had it been possible to convict a single Mollie Maguire in any court where they were brought to trial.
Another crime which McParlan was sent to investigate was the murder of Morgan Powell, at Summit Hill, Carbon County, which occurred December 2, 1871. These were enough to occupy the time of a man even as clever as Detective McParlan alias James McKenna.
During the more than two years that McParlan lived among the Mollies he did not learn the murderers of Littlehales but succeeded in bringing to justice many other murderers.
The arrests quickly followed one another when once begun early in 1876. The trials began in Mauch Chunk in March. While McParlan did not testify in the first case he furnished very valuable information, and greatly assisted the prosecution.
Then followed the arrest and trial of others in Pottsville, Mauch Chunk and Bloomsburg with the conviction of many.
McParlan went upon the stand in the trial of James Carrol, Thomas Duffy, James Roarty, Hugh McGehan, and James Boyle, for the murder of B. F. Yost, which occurred at Tamaqua, July 6, 1875. This trial was held at Pottsville, before a full bench of Hon. C. L. Pershing, D. B. Green and T. H. Walker. James Kerrigan, a Mollie, was a witness for the Commonwealth.
The trial of Thomas Munley in June, 1876, in the same court, for the murder of Thomas Sanger and William Uren, brought Mr. F. B. Gowen into the case and the delivery of his wonderful speech, which will ever remain one of the greatest in the history of the criminal courts of our State.