In 1882, James Overton Broadhead ran for Congress against John Glover. The "St. Louis Post-Dispatch", at Cockerill's direction, ran a number of articles questioning Broadhead's role in a lawsuit between a gaslight company and the city; Broadhead never responded to the charges. Broadhead's friend and law partner, Alonzo W. Slayback, publicly defended Broadhead, asserting that the "St. Louis Post-Dispatch" was nothing more than a "blackmailing sheet." The next day, October 13, 1882, Cockerill re-ran an offensive "card" by John Glover that the paper had published the prior November (November 11, 1881). Incensed, Slayback barged into Cockerill's offices at the paper demanding an apology. Cockerill shot and killed Slayback; he claimed self-defense, and a pistol was allegedly found on Slayback's body. A grand jury refused to indict Cockerill for murder, but the economic consequences for the paper were severe. Therefore, in May 1883, Pulitzer sent Cockerill to New York to manage the "New York World" for him.