Pottawatomie massacre

The Pottawatomie massacre happened on the night of May 24, 1856. John Brown and a number of volunteer Free-Staters attacked and murdered five men in a small settlement on the Pottawatomie Creek near Osawatomie, Kansas. The killings were particularly brutal. One by one, settlers were dragged from their homes and hacked to death with broadswords and shot. The victims were pro-slavery, but were not slave owners themselves. The murders were in response to pro-slavery Missouri Border Ruffians who burned and looted Lawrence, Kansas three days earlier. It happened just two days after the Caning of Charles Sumner, the Senator from Massachusetts on the floor of the United States Senate. The Pottawatomie massacre was one of the many bloody episodes in Kansas preceding the American Civil War. It marked the beginning of the period called Bleeding Kansas. 
Background.
The Territory.
In 1854, the Missouri Compromise, which had restricted the expansion of Slavery in the United States, was done away with by the Kansas–Nebraska Act. Based on the doctrine of popular sovereignty, the federal government allowed the issue of slavery to be decided by those settling the Kansas Territory. By popular vote the people who lived there would decide whether Kansas would become a "slave-state" or be a "free-state" (free of slavery). Pro-slavery Missourians, Free-Staters and abolitionists all poured into Kansas. Soon, the different sides held their own elections and set up two opposing territorial governments. In May 1856, a drunken mob of pro-slavers sacked the town of Lawrence. Brown was enraged at this and wanted vengeance.
John Brown.
Brown was a deeply religious man who spoke his mind. As an abolitionist he found slavery in any form to be immoral. He fathered 20 children and with his wife moved to Kansas Territory to wage a war against slavery. He arrived on October 7, 1855, to help several of his sons who were already there to set up land claims. Along the way he got funds from other abolitionists and bought a large number of guns and swords for the fight he was sure would come. He had spoken out before against the Southern plantations and had called for the execution of slave catchers. Kansas, he thought, would be the perfect place to put his words into action.
When the town of Lawrence was sacked, Brown became extremely angry. He could not understand why the people of Lawrence had not decided to fight. He decided he and his followers would avenge the sack of Lawrence. 
The massacre.
On the night of May 24th, 1856, Brown set out with seven others to the pro-slavery town of Pottawatomie Creek. They were armed with swords and rifles. One by one the victims were dragged out their beds and murdered by Brown and his followers. They attacked three different farm houses. 
James Doyle and two sons were dragged outside their house and hacked to death. Mrs. Doyle, her daughter and a 14-year old son were not killed. They next went to Alan Wilkinson's farm where he was taken "prisoner". His sick wife and two children begged Brown not to kill him. Brown's men took his rifle and two saddles, but let Wilkinson live. James Harris owned the third house Brown visited that night. Haris, his wife and young child plus three other men were living there. Brown's men killed one man, William Sherman, then took their weapons, a saddle and one horse. Brown's followers included four of his sons who all later claimed that Brown himself did not actually murder anyone. But he was the leader and he made all the decisions of who would live and who would die. They washed the blood from their hands and their swords in the creek, then went home. None of the killers were ever prosecuted for the crime. 
Aftermath.
After the massacre, pro-slavery forces launched a manhunt for Brown. They destroyed the Browns' property and Brown's son Frederick was shot and killed. Brown escaped Kansas and fled north. Together, the sack of Lawrence and the Pottawatomie massacre started a civil war in Kansas. Brown gained national attention and fame among abolitionists. He was able to gather men and arms for another "secret mission"; John Brown's raid on Harpers Ferry.
In November 1859, as Brown was waiting to be executed for his raid on Harpers Ferry, he received a letter. It was from Mahala Doyle, whose husband and two sons Brown killed: