A Webb City Murder and the "Unwritten Law"

After J. W. “Will” Costley was arrested for killing Benjamin Newman in October 1909 at a boarding house run by Costley’s wife in Webb City, the defense invoked the so-called “unwritten law,” a principle widely cited to justify homicide arising from affairs in which the victim had offended a man’s honor, a woman’s virtue, or the sanctity of marriage. Costley claimed he’d caught Newman sleeping with his wife, but Costley and his wife were separated. Would the “unwritten law” still apply in his case?

Costley and his wife, Mary, ran a boarding house on North Webb Street in the booming mining town of Webb City. Sometime in early October 1909, the couple got into a big fight that led to a separation, and Costley was charged with assault. Released on bond, he wouldn’t leave Mary alone. He was especially upset by the attention Benjamin Newman was paying to his wife, and he made threats against both of them.

After the separation, Mary continued to run the boarding house. One of her roomers was miner Ralph Page, and late Saturday night, October 23, Newman accompanied Page home. About midnight Page fell asleep on the lounge where Mary normally slept, leaving Newman and Mary still awake. About three hours later, Costley slipped into the house through a window and found Newman and Mary in bed asleep together in a room adjoining the one where Page was. Retrieving a heavy gas pipe, Costley roused Newman and Mary and attacked Newman with the pipe when he sprang up in bed.

Mary fled upstairs screaming for the two young women who roomed there to help her because Costley was “killing the men.” The two women started downstairs but were met by Costley, who ordered them back upstairs “where they belonged.” Meanwhile, Newman staggered from the house with a broken nose and several severe gashes in his head. The commotion also aroused Page, and either he or the severely wounded Newman alerted authorities.

Costley surrendered to two officers who arrived on the scene, declaring, “I caught that fellow with my wife.” Charged with felonious assault, he was taken to the county jail at Carthage to await a preliminary hearing. On Monday, October 25, Costley was taken before a justice on the prior charge of assaulting his wife. He was sentenced to ten to twenty days in jail on a reduced charge of disturbing the peace. Three days later, Newman died at the Salvation Army Hospital in Webb City, and the second assault charge against Costley was promptly upgraded. In early November, as soon as his sentence for disturbing the peace of his wife expired, he was re-arrested on a second-degree murder charge.

At his preliminary hearing on November 19, Costley was ordered held for trial, and he was returned to the Carthage jail. Arraigned in circuit court at Joplin in early January 1910, Costley pleaded not guilty, and the judge ordered him held without bond. When his trial got underway in Joplin in mid-February, Mary Costley did not appear, either as a witness or as a spectator.

The main state witnesses were other occupants of the Costley boarding house, including Ralph Page. Page said he did not actually witness the attack on Newman and had no knowledge of the events directly leading up to it. The two officers who had arrested Costley testified, however, that he confessed the attack to them, and the defense did not deny this fact.

Instead, Costley’s lawyers, in addition to invoking the “unwritten law,” claimed self-defense. Costley took the stand and declared that, upon discovering his wife in bed with Newman, he retrieved the metal pipe because he was afraid to approach the man unarmed. Then, when he roused Newman from his sleep to demand an explanation, Newman reached beneath a pillow for a revolver. As he started to pull the revolver from its hiding place, Costley struck him with the gas pipe.

The jury received the case late Friday afternoon, February 18, and reported back Sunday morning, after deliberating throughout the day on Saturday, that they could not reach an agreement. The judge declared a mistrial. One report said the jurors agreed on conviction but were deadlocked on the punishment, while another said they disagreed on the defendant’s guilt. “In any event,” observed the Webb City Register, “it is felt that the unwritten law saved William Costley from serving a term in the state prison for killing Ben Newman.”

When Costley’s second trial began in Joplin at the May 1910 term of court, “little interest” was shown in the proceedings, and testimony in the case, as in the first trial, consumed only a few hours. Despite the court’s admonition against invoking the so-called “unwritten law” as a defense, Costley’s lawyers wove it “surreptitiously into evidence and addresses to the jury.” And contrary to the judge’s instructions, the state introduced evidence concerning Costley’s assault on his wife a few weeks prior to Newman’s killing to undercut the “unwritten law” defense, suggesting that the Costley marriage had already been defiled before Newman came on the scene.

The jury this time found Costley not guilty, surprising many observers who thought the outcome would be another hung jury. In fact, the jury was split at first, but those holding out for a guilty verdict were finally persuaded to the defendant’s side. Mrs. Costley, who had not previously appeared during the trial and had also not attended most of the first trial, was in the courtroom beside her husband when the verdict was announced.

This article is condensed from a chapter in my latest book, Midnight Assassinations and Other Evildoings: A Criminal History of Jasper County, Mo.