The Boston Massacre

The Boston Massacre occurred on March 5, 1770, where British redcoats fired into a crowd of colonists, killing five. The event was caused by the growing tensions between the redcoats and the colonists, who were upset over the growing presence of British soldiers among them, who had been sent to enforce the Townsend Acts, which imposed duties on glass, lead paint, paper, and teas that were imported to the colonies. By the colonists, these acts were seen as unfair and an abuse of Britain's power .
An angry riot began when a group of fifty citizens attacked a British group of soldiers.  The mob began to throw sticks, snowballs, and stones at the group of soldiers, and one of the officers, Captain Thomas Preston called for more soldiers to arrive at the scene. Those soldiers were also attacked, leading to them firing into the crowd, killing three right away and wounding eight (two of which would later die).
Two of the officers were convicted of manslaughter, while Captain Preston was tried, but not charged for murder.
The Boston massacre was later sensationalized in order to create the appropriate outrage from the American public.  The most famous was the depiction of the event, an engraving made and circulated through newspaper by Paul Revere, who was not even at the massacre himself. The engraving depicted the mob as powerless and the British as angry killers.  The Sons of Liberty used the massacre as a piece of propaganda against the British, and pushed the British and the colonists even closer to a Revolutionary War.  The Paul Revere image can be seen here below.


Sources:
http://www.bostonmassacre.net/
http://www.ushistory.org/declaration/related/massacre.htm
http://www.landofthebrave.info/boston-massacre.htm
http://www.history.com/topics/american-revolution/townshend-acts
http://www.bostonteapartyship.com/paul-revere