Several months later, in February, 1925, Judge Thayer asked Van Amburgh to reinspect Sacco's Colt to determine its condition. With the district attorney present, Van Amburgh took the gun from the clerk and started to take it apart. At this time Van Amburgh realized that the barrel to Sacco's gun was brand new. There was even a film of cosmoline on it.
Two days later, Judge Thayer began private hearings to determine who had tampered with the evidence. The hearings lasted three weeks. Hamilton had no choice but to admit that the new barrel must have come from one of his pistols. He insisted, however, that he had not made the switch, accusing some unknown person associated with the prosecution. Hamilton then examined the old barrel that had somehow gotten onto one of his new guns and unabashedly asserted that it wasn’t the barrel from Sacco's Colt automatic.
When the smoke had cleared, everyone in the courtroom, including the defense attorneys, realized that Hamilton had made the switch. The prosecution theorized that Hamilton had make the substitution with the idea of making the discovery himself for purposes of demanding a new trial.16
At the conclusion of the hearings, Judge Thayer reserved judgment as to who had made the switch. He held that the old barrel on the new pistol was Sacco's and had it returned to the correct weapon.
Albert Hamilton would continue his association with the defense, but would no longer play an important or active role in the case. He had destroyed his credibility, albeit undeserved, as a firearms expert and as a witness. He was now a monumental liability and embarrassment to the defense. If the public had gotten wind of his chicanery, it could have significantly set back the emerging science of firearms identification, a field that was already harboring too many hacks, incompetents, and frauds. Disclosure might also have destroyed Calvin Goddard's opportunity to come into the case as the only true professional in the field. If Hamilton's act had become public knowledge, Goddard himself may have been tarnished and his work discredited.
The barrel switching incident apparently had little or no effect upon Hamilton's career, because eight years later he was testifying for the defense as a firearms expert in a Hopkinton, New York murder case. The defendant, on whose behalf Hamilton had testified, died in the electric chair one year later.
In the spring of 1924, one year after the Hamilton-Proctor Motion in the Sacco-Vanzetti case, Judge Thayer denied this and all of the other motions for a new trial. The Hamilton-Proctor Motion may have been the best shot the defense had for a new trial, but the barrel-switching episode may have tilted the scale, or at least given Judge Thayer the excuse he needed to deny all of the motions for a new trial.
16. The most thorough account of Albert Hamilton's barrel-switching stunt is found in Chapter V, “An Unpublished Chapter in the Record,” in The Legacy of Sacco and Vanzetti by Louis Joughin and Edmund M. Morgan (NY: Harcourt, Brace and Co., 1948). Although the authors of the above book are sympathetic to Sacco and Vanzetti, they concede that Albert Hamilton was a phony scientist and an unreliable witness.
17. The case in which Hamilton testified involved the May 30, 1932, murder of Charles Witherell by his son Stephen. When initially questioned by the New York State Police, the son quickly admitted to shooting his father at point blank range with a Remington high-powered rifle he had stolen from his cousin. The Remington rifle was identified as the murder weapon by a firearms expert from the New York City Police Department. When the son took the stand at his trial, he denied shooting anyone and claimed that the body in his father's bed was not his father. This absurd defense was made possible by the fact that the dead man had not been discovered until a week or so after the crime. Decomposition and the massive gunshot wound to the head had made the body unrecognizable by sight. Hamilton testified that there were two gunshot wounds on the body, the head wound caused by the rifle, and a wound on the victim’s hand, made by a handgun. As it turned out, there was no hand wound at all, the victim had been missing two fingers long before his death. Stephen Witherell was executed in Sing Sing on August 17, 1933. For a detailed account of this case, see: McCann, Charles B., (as told to Roy G. LaFave) “New York’s Memorial Day Murder Mystery,” True Detective Mysteries, (February, 1935) pp 50-3, 88-9.