Preceding the incident at the Boston Customs House, tensions between British authorities and Bostonians had grown around resistance to the Townshend Acts, laws entitling the British levy trade taxes. The most visible figures of British authority were customs officials, and they became the target of local animosity. In 1768, a British warship was sent to Boston to protect customs officials, whereupon the British navy began impressing Bostonians into military service, further inflaming tensions.
On Feb. 22, 1770, an 11-year-old servant named Christopher Seider began heckling a store fort selling British goods. Boston customs official Ebenezer Richardson rebuked him, and Seider later showed up in front of Richardson's home. Seider was joined by more boys who were later joined by adults. The crowd threw a rock through Richardson's window; and he fired a load of birdshot out his window to disperse the crowd, killing young Seider. The incident was fanned into a political cause by local patriots and was on the lips of the March 5 crowd that surrounded the King Street Customs House.
A merchant's apprentice named Edward Gerrish positioned himself outside the King Street Customs House on March 5 and shouted at the officer inside -- Lt. John Goldfinch -- that Goldfinch had bilked Gerrish's master -- a wigmaker -- on a bill. The charge was untrue, as later established during a trial, and Goldfinch ignored Gerrish. An angry Gerrish left and returned with several companions. A private, Hugh White, was now guarding the customs house alone. Gerrish and his companions argued with White, and White struck Gerrish across the face. More Bostonians joined the group, and by evening the angry crowd had grown to more than 300. Pvt. White had been left alone and was facing the hostile crowd that had focused its animosity on him. White was forced to lock himself in the customs house, whereupon a detachment of seven soldiers was sent from the Main Guard to protect him.
The crowd threw things at the soldiers, who had fixed bayonets to hold the Bostonians back. One innkeeper named Richard Holmes clubbed a soldier, who fired a round. In the ensuing melee, several rounds were fired -- apparently without coordination or command -- and three men were killed: Crispus Attucks, a local "mulatto" mariner; Samuel Grey, a local rope maker; and James Caldwell, an intoxicated sailor. A young man named Samuel Maverick died hours later from a wound, and an Irishman named Patrick Carr died two weeks later. The next day, the British removed all troops from town.