There could be a variety of editorial titles you could use in reference to the Boston Massacre. While it is clear the British soldiers fired at the colonists and killed five of them, the colonists had some role causing the events at the Custom House to occur that evening. The colonists were pressing closer to the soldiers guarding the building. They were throwing snowballs at the soldiers as well as yelling insults at them. Thus, both the British soldiers and the colonists share in some of the blame for the events that evening.
Your editorial title will depend on what side your editorial is supporting. If you are writing in support of the colonists, your title might read “Massacre in Boston Means its Time for a Change” or “There Is No Looking Back After the Bloody Massacre.” You might even say “Bloody Murder Is Now A Turning Point.” Then you would write an editorial in support of the colonists.
If you are supporting the British, your title will look very different. You title might read “Mob Action Forces The British Hand” or “Wild Colonists Must Be Tamed.” You might even write an editorial with a title of “Unruly Colonists Cause Violent Confrontation.” You then would go ahead and write an editorial supporting the British government and the British soldiers.
With suggested titles like these, you should now be able to write an editorial supporting one side or the other.