On the evening of March 5, 1770, an altercation began outside the Custom House on King Street (now State Street) when a wig maker's apprentice accused a British officer of failing to pay a bill. Private Hugh White was the British sentry on duty outside the Custom House, and he tried to intervene, leading to an exchange of insults. White struck the young boy on his head with the butt of his musket, inciting anger among the bystanders and attracting a crowd.
As the evening progressed, the crowd around Private White grew larger and more boisterous. They began throwing objects at him and taunting him. White retreated to the steps of the Custom House and called for assistance. A runner carried the message to Captain Preston, who assembled a small detachment of seven members—one non-commissioned officer and six privates from the 29th Regiment of Foot—and led them to the Custom House to reinforce White and restore order. The soldiers arrived with fixed bayonets, a show of force intended to disperse the increasingly hostile crowd. However, the confrontation continued to escalate. By this time, the number of colonists had grown into the hundreds, and they were throwing ice, snow, and objects at the soldiers and daring them to fire at the crowd.
Private Hugh Montgomery was one of the soldiers dispatched with Captain Preston to the scene of the altercation. During the confrontation with the crowd, Montgomery was knocked to the ground, reportedly by a club or a stick. In reaction to being struck, Montgomery regained his footing and fired his musket into the crowd. After a brief pause, other soldiers also fired into the crowd, either in confusion or following perceived orders. The chaotic gunfire resulted in the deaths of three civilians—rope maker Samuel Gray, mariner James Caldwell, and a mixed-race sailor named Crispus Attucks—almost immediately. Two others, Samuel Maverick and Patrick Carr, succumbed to their injuries later.
Captain Thomas Preston retreated with his men, who took up defensive positions in front of the state house. In the immediate aftermath, with tensions still high and the potential for additional violence looming, Governor Thomas Hutchinson arrived on the scene. He addressed the crowd, promising a fair inquiry and trial for the soldiers involved if the townspeople would disperse and restore peace. His assurances helped to quell the immediate unrest, and the crowd began to disband, though the promise of justice did little to dampen the long-term outrage that the incident had sparked.