On August 8, 1850 a hired carriage was forcibly stopped in the middle of Brookeville Pike (Georgia Avenue) near this spot by a Sheriff's posse from Washington, D.C. and a shoot-out ensued. The carriage was driven by William Chaplin, who was unarmed, and was carrying two men attempting to escape from slavery; Garland White, belonged to Senator Robert Toombs of Georgia, and Allen, belonging to Senator Alexander H. Stephens of Georgia. The posse consisted of six men led by John Goddard who were heavily armed and shot into the carriage after stopping it by ramming a fence rail through the wheel spokes. At least one of the fugitives returned fire before jumping from the carriage and running away. Mr. Chaplin was hauled from the carriage and beaten. Both African-Americans were slightly wounded as was one of the members of the posse. Allen was returned to his owner, and Garland White turned himself in three days later. White later escaped and served as chaplain for the 28th regiment, U.S. Colored Troops in the Civil War.
William Chaplin was a leader of the Liberty Party and active in the Albany Vigilance Committee. He had come to Washington from New York four years earlier to take the place of Charles Torrey, an abolitionist and operative on the underground railroad, who died in prison in 1846. Chaplin had been active during that time helping fugitives escape an purchasing slaves in order to free them with money provided by the Vigilance Committee. He arranged the ill-fated flight from Washington, D.C. of 77 enslaved people aboard the ship Pearl in 1848.
Since there was originally some dispute over whether the arrest took place in D.C. or in Maryland, Chaplin was imprisoned in Washington for six weeks and released on $6,000 bond, and was subsequently imprisoned in Maryland for thirteen weeks and released on $19,000 bond on December 24, 1850. The bond money was raised by fellow abolitionists. Chaplin left the area when released, forfeiting the bond, and never came to trial.