There was much interest in the case and the public generally sympathized with Muybridge. Among the many spectators were numerous friends of Muybridge, as well as people who wished to see Larkyns' name cleared and the murderer punished. Flora had filed for divorce on 17 December on the ground of extreme cruelty, but this first petition was dismissed. Judge F.W. Wallace presided. Judge Thomas P. Stoney and district attorney D. Spencer represented the prosecution. The defense was led by W.W. Pendergast (a friend of
Leland Stanford), with Cameron H. King and E.S. Gottschalk as assistant counsel. The defendant had pleaded "not guilty", with the defense admitting to the murder but pleading for an acquittal on grounds of insanity. A jury of twelve men had been assembled with little difficulty, in a very short time. The defense argued against the insanity plea. It was impossible that Muybridge had gone insane after receiving proof for his dishonor, if he afterwards had quietly conversed with witness Harry Edwards and informed about business options.
The defense Muybridge's attorneys intended to prove that Larkyns had been a man of bad character and deserved his fate. Larkyns seduced Mrs. Muybridge under false pretenses, claiming to be a married man and luring Flora to his lodgings. He boasted about it to friends. Learning about the depth of the deceit made Muybridge insane from anger, to the point that he passionately decided to kill the destroyer of his happiness, loving his wife deeply, only living for her. Muybridge had been prone to insanity since a stagecoach accident in 1860, his hair had turned grey in three days and he never was the same ever since. All the witnesses related incidents that illustrated Muybridge's eccentricities. Mrs. Smith told how one day Muybridge came home, looked happily at his wife and child, then suddenly got confused over who had fed the canaries. After being told that he himself had done so, he replied "Ah dear me, I feel bad here sometimes" while pointing at his forehead. Rulofson referred to a picture of Muybridge sitting on the edge of a rock in Yosemite, where he could easily fall 2,000 feet. Rulofson, portrait photographer Silas Selleck and several other friends and long-time acquaintances testified that Muybridge's personality was dramatically changed after his 1860 stagecoach accident and consequent stay in Europe. He had turned from a genial, pleasant and quick business man into an unstable and erratic photographer. In his two-hour closing address, W.W. Pendegast's asked the jury, at the request of the defendant, to either acquit Muybridge for any crime or to send him to the gallows, like the district attorney had proposed. Although the law did not offer a statute "permitting a man to slay his injurer. But, law or no law, every fiber in a man's frame impels him to instant vengeance" at all cost. Muybridge had not just killed Larkyns for revenge, but also to protect his wife against the debauchee who kept pursuing her, as evidenced in Larkyns' letter.
Verdict The judge gave the jury four optional verdicts to choose from: "guilty of murder in the first degree" punishable by death, another conviction for murder with punishment by lifelong imprisonment, "not guilty" or "not guilty on account of insanity". He also pointedly instructed the jury that even if Larkyns had seduced Muybridge's wife, the defendant was not justified to take the law into his own hands. After a long first jury meeting, they stood five for conviction and seven for acquittal, before retiring for the night at 23:00. The next morning they arrived at the agreement that the murder was justified, but they could not immediately decide whether or not Muybridge had acted out of insanity. The eventual acquittal was explained by arguing that if their verdict was not in accordance with the law, it was in accordance with the law of human nature. They felt they could not punish a person for doing something that they themselves would do in similar circumstances. ==Public opinion and press coverage==