It was now necessary for the detectives to devise a new plan. Robert Pinkerton knew that some three years earlier Donahue had been concerned in the robbery of a bank at Winnipeg, and also in the robbery of a hardware store at Quebec. His brother, William Pinkerton, he also knew, had a personal acquaintance with Donahue, from having arrested him a number of years before. He therefore sent for William Pinkerton to come to New York from Chicago, and on his arrival proposed to him that he go to Fort Erie, get an interview with Donahue, and tell him of Proctor's treachery in betraying Collins and himself; impress upon him that Proctor was a dangerous man to have dealings with; and try to induce him to lend his aid in delivering Proctor and Collins over the line, just as Robert Pinkerton had sought to have Proctor do in the case of Donahue and Collins. Donahue was known as a "stanch" man,—that is, one who is true to his friends,—and it was thought probable that he would refuse to take part in any such scheme. But in that event William Pinkerton was to threaten him with arrest for the old robberies at Winnipeg and Quebec.
This plan was carried out by William Pinkerton with greater success than had been expected. At first Donahue stoutly refused to betray a comrade, but the danger threatening himself was made to appear so great that finally, seeing no other way out of his difficulties, he consented to do what was asked of him in regard to Proctor. Against Collins, however, he declined to give any aid. By working on Proctor's natural fear of arrest, he easily persuaded him that the immediate departure of all three of them—himself, Proctor, and Collins—for Europe was advisable. It was arranged that they should not sail from Quebec or Halifax, since the steamers from those points were likely to be watched by detectives, but that they should leave Fort Erie stealthily by night, make their way separately to Montreal, and meet there.
This plan was carried out, and within a few days the three were in Montreal, all apparently of one mind in their desire to escape the country, though in reality Proctor was the only one of the three who thought himself in danger. Donahue had taken Collins into his confidence, and Collins was quite of Donahue's opinion that they were doing the proper thing in saving themselves by surrendering a man who had shown himself willing to betray them.
It had been agreed between William Pinkerton and Donahue that at Montreal tickets should be purchased to Europe by way of Portland, Maine, and that the party should leave Montreal at a certain time by the Grand Trunk road. The line of this road runs for a number of miles through northern Vermont, and it was customary for the train the men were to take to wait over for an hour at Island Pond, a little place just across the Canadian line. Here, as it was arranged, Robert Pinkerton was to be waiting, ready to take Proctor into custody, and also (though in this part of the arrangement Donahue, of course, was not consulted) Donahue and Collins, should they be so imprudent as to stay on the train until it crossed the line. To the forwarding of this latter end, indeed, a special stratagem was resorted to. Conceiving that Donahue and Collins, in order the more completely to allay Proctor's suspicion, might remain with him until the last station was reached on the Canadian side, the detectives arranged that on this particular night the train should not stop at that station, but push on at full speed to the American side.
On a certain Tuesday night, Donahue, Collins, and Proctor took the 10:15 p. m. train at Montreal for Portland. No sooner had they left the station than a Pinkerton representative, who had "shadowed" them aboard, telegraphed the fact to Robert Pinkerton at Island Pond. Proctor went early to his berth in the sleeper. In another berth, not far distant, never closing his eyes through the night, but lying there fully dressed, with weapons ready, was a Pinkerton detective, whose instructions were to accompany the three robbers as long as they were together, and to stay with Proctor to the last.
It was five o'clock in the morning when the train drew up at Island Pond. On the platform stood Robert Pinkerton, carrying a requisition from the governor of Pennsylvania on the governor of Vermont for the arrest of Donahue, Collins, and Proctor, charged with robbing the United States Express Company of forty thousand dollars, at Susquehanna, Pennsylvania. The first man to leave the train was the "shadow," who informed his chief that Proctor was sound asleep in berth No. 12. Donahue and Collins, he said, had left the train long before it reached the last station on the Canadian side, so that the plan for their capture had fallen through. Mr. Pinkerton went aboard the sleeper at once, and going to berth No. 12, pushed aside the curtains. He could not see distinctly for the darkness, but borrowing a lantern from one of the trainmen, let the light fall on the face of the person within, and saw it was Proctor, slumbering in complete unconsciousness that his hour of reckoning had come. A gentle push in the ribs awakened him with a start. Recognizing Mr. Pinkerton, he said with admirable coolness:
"You have spoiled the whole business. If you had not come in here to arrest me, I would have had those men across the line next week."
When he said this, Proctor supposed that Donahue and Collins were asleep in an adjoining berth; but, even to save himself, he never thought of betraying them, which goes to show that he was a "stancher" man than Donahue and Collins had been led to believe. For some time he endeavored to maintain his old character with Mr. Pinkerton; but on the way to Susquehanna, realizing the hopelessness of his case, he acknowledged the deception he had practised, and his full responsibility with the others in the Susquehanna robbery. He also admitted his previous criminal record.
At Susquehanna, Proctor was placed in jail to await trial, and there Mr. Pinkerton visited him some time later. Something in the prisoner's manner convinced the detective that all was not as it should be, and he urged the sheriff to put Proctor in another cell and search his clothes and his cell thoroughly. This was done, and there were found a number of keys that fitted the locks of various doors in the jail, and also a large key fitting the gate from the jail-yard into the street. Proctor's rare mechanical skill had enabled him to make these keys in his cell, from impressions furnished him by a woman who had been allowed to visit him. Being a good talker, Proctor had won this woman's sympathy, and had also made a strong appeal to her self-interest by promising, on his escape, to share with her a large sum of money he had buried.
At his trial Proctor pleaded guilty, and was sentenced to twelve years' imprisonment in the penitentiary at Cherry Hill, Pennsylvania. Here, again, he was caught in the act of making keys to aid him to escape. He laid various other plans for regaining his liberty, indeed, but all were frustrated. His imprisonment worked no reform in him. After he had served out his sentence, some burglaries committed in Maine brought him again under arrest, and, having been identified as a convict from the Massachusetts State prison, he was taken back to that institution, to serve out his unexpired sentence.