His raid in October 1859 involved a band of 22 men who seized the Federal armory at Harper's Ferry, Virginia (since 1863, West Virginia), knowing it contained tens of thousands of weapons. Brown believed the South was on the verge of a gigantic slave uprising and that one spark would set it off. Brown's supporters George Luther Stearns, Franklin B. Sanborn, Thomas Wentworth Higginson, Theodore Parker, Samuel Gridley Howe, and Gerrit Smith were all abolitionists, members of the so-called Secret Six who provided financial backing for Brown's raid. Brown's raid, says historian David Potter, "was meant to be of vast magnitude and to produce a revolutionary slave uprising throughout the South". The raid did not go as expected. He hoped to have quickly a small army of runaway slaves, but made no provision to inform these potential runaways, although he got a little local support. Lt. Colonel Robert E. Lee of the U.S. Army was dispatched to put down the raid, and Brown was quickly captured. He was tried for treason against the Commonwealth of Virginia, murder, and inciting a slave revolt, was found guilty of all charges, and was hanged. At his trial, Brown exuded a remarkable zeal and single-mindedness that played directly to Southerners' worst fears. Under Virginia law there was a month between the sentencing and the hanging, and in those weeks Brown spoke gladly with reporters and anyone else who wanted to see him, and wrote many letters. Few individuals did more to cause secession than John Brown, because Southerners believed he was right about an impending slave revolt. The day of his execution, Brown prophesied, "the crimes of this guilty land will never be purged away but with blood. I had as I now think vainly flattered myself that without very much bloodshed it might be done."