Four months after his arrest, Hauptmann was tried for murder in the small town of Flemington, New Jersey. The sensational trial produced front page headlines all over the world. Since there were no eyewitnesses to the crime and Hauptmann hadn't confessed, the evidence against him was purely circumstantial. Eight handwriting experts, including Albert S. Osborn and John Tyrrell, testified that Hauptmann had written the fifteen ransom notes. A federal wood expert from Madison, Wisconsin named Arthur Koehler, testified that a portion of the kidnap ladder had come from Hauptmann's attic floor. Koehler also testified that the tool marks on the kidnap ladder had been made by some of Hauptmann's carpenter tools.
The Hauptmann defense, including his own testimony, was incredibly weak and at times bordered on the ridiculous. On February 13, 1935, the jury found Hauptmann guilty of First Degree Murder. He was sentenced to death. Because of the physical evidence and all of the expert testimony, the Hauptmann trial was considered a criminalistic triumph.
After losing several state and federal appeals, Hauptmann was scheduled to die in January, 1936. A few weeks before the execution was to take place, New Jersey Governor Harold G. Hoffman announced that he was granting Hauptmann a thirty day reprieve. Hoffman said the case had been bungled by the New Jersey State Police and that he was launching his own independent investigation.
In December, less than a month before he was to be executed, Hauptmann had written a letter to the governor asking for a lie detector test. Early in January, about a week before the New Jersey Court of Pardons was to hear Hauptmann's plea for clemency, Hauptmann's wife Anna took a train to Chicago to see Leonarde Keeler.
In order to convince Mrs. Hauptmann that the polygraph worked, Keeler conducted several of his demonstrations. When she returned to New Jersey, Anna told Bruno that she was impressed with Keeler and his lie detector device. She informed her husband that Keeler would come to the prison and test him free of charge. Keeler had also promised not to make his involvement in the case public. Governor Hoffman was excited about the idea and said he'd make the necessary arrangements to get Keeler into the death house.
In the meantime, Keeler leaked the story to the press and the next day newspapers were reporting that the famous detector of lies had tested Mrs. Hauptmann and was about to examine the condemned man himself. One reporter even implied that once Mrs. Hauptmann realized the polygraph worked, she decided against having the instrument used on her husband. By jumping the gun on the publicity, Keeler had killed his chance to perform what would have been one of the most celebrated polygraph tests in history.
On January 23, 1936, with the first week of Governor Hoffman's reprieve already gone, William Marston, the Boston attorney and lie detection pioneer, arrived in Trenton to discuss a Hauptmann test with the governor.
Marston's method, based solely on changes in a subject's blood pressure, was not nearly as sophisticated and reliable as Keeler's. Nevertheless, Governor Hoffman was impressed with Marston who set his fee at a hundred dollars a day. Marston said his examination would take at least two weeks.4
Marston met with Governor Hoffman then spoke to reporters: "I have no conviction as to Hauptmann's guilt or innocence. I do think he knows more than he has told, and the problem is to get at that secret stored in his mind. Frankly, I hope to get a confession, provided I am given a proper opportunity to apply the test."
Marston had agreed not to divulge the results of his test to the press or to the New Jersey State Police. Any clues derived from his examination could then be checked out first by the Governor's private investigators without any interference from the real police.
When Governor Hoffman started arranging Marston's visit to the death house, he ran into a problem. Under New Jersey Law, the only person allowed to visit an inmate on death row were his relatives and lawyers. Exceptions to this rule had to be in the form of a special order from the trial judge. Hoffman promptly requested such permission and it was quickly denied.
The only way Marston could get in to see Hauptmann was to be appointed associate counsel for the defense. The Governor considered the appointment but changed his mind when he realized that as one of Hauptmann's attorneys, Marston would lose his objectivity and credibility as a lie detection expert. His findings would be rendered invalid and therefore useless.
Marston returned to Boston and the idea of unlocking Hauptmann's mind through scientific lie detection was dropped for good.5
On April 3, 1936, Hauptmann was led into the death house at the New Jersey State Prison at Trenton and electrocuted. He died without confessing his crime and to this day, many wonder if he had been the kidnapper.
Although it wouldn't have solved the case any sooner, Schwarzkopf would have benefited from the polygraph. He would have known early on that none of the servants had anything to do with the crime.
It's also a shame that Keeler didn't test Hauptmann. Assuming that Hauptmann would have submitted to a test, He would have denounced the results had they not suited him. The polygraph wouldn't have eliminated the controversy associated with the case; nevertheless, it would have been interesting to know if Keeler's results confirmed Hauptmann's guilt.
When August Vollmer asked John Larson to make a lie detector machine, he must have had in mind cases like the Lindbergh Kidnapping. Had Hauptmann been seriously confronted with the polygraph, at least before his trial, he probably would have refused to take it. Had he taken the test while on death row, critics would have claimed, regardless of the outcome, that a man facing the electric chair is not a proper subject.
At any rate, in the short, turbulent history of the polygraph, the Lindbergh Case could be considered a missed opportunity.