Indian Wars Silas Stillman Soule (/soʊl/ SOHL; July 26, 1838 – April 23, 1865) was an American abolitionist, a teenage 'conductor' on the Underground Railroad, military officer, and an early example of what would later be called a whistleblower.

As a Kansas Jayhawker, he supported and was a proponent of John Brown's movement in the time of strife leading up to the American Civil War.

Soule was in command of 1st Colorado Cavalry, Company D that was present at Sand Creek and the massacre of Native Americans that occurred there on November 29, 1864.

Soule was a "...friendly, intelligent, and good-natured young man, full of practical jokes, [and] tall tales...[2] In 1854, his family became part of the newly formed New England Emigrant Aid Company, an organization whose goal was to help settle the Kansas Territory and bring it into the Union as a free state.

[3] Shortly after the family's arrival at Coal Creek located a few miles south of Lawrence,[a] Silas's father, Amasa, established his household as a stop on the Underground Railroad.

Brown told Soule, however, that he had already decided to become a martyr for the abolitionist cause and would willingly allow himself to be hanged, hoping his death would help bring on a war between North and South.

Nonetheless, pastor and Secret Six member, Thomas Wentworth Higginson, an associate of Soule's, put together a rescue attempt of two men who had also been incarcerated along with Brown, Albert Hazlett and Aaron Dwight Stevens.

After his release from the Charles Town jail, Soule traveled to Boston, where he often met with various abolitionists and befriended the poet Walt Whitman.

[6] In 1861, after the start of the Civil War, Soule enlisted in Company K; 1st Colorado Infantry,[e] and took part in the New Mexico campaign of 1862, including the key Battle of Glorieta Pass.

Before the attack, Soule told other officers “any man who would take part in [such] murders, knowing the circumstances as we did, was a low lived cowardly son of a bitch.” [7] Several lieutenants also objected to Chivington's plans.

[1] As the attack began, Soule reminded his troops that the supposed "enemy" was a peace chief's band, and some responded that they "would not fire a shot today".

Soule's and others' verbal and written testimonies about the Sand Creek Massacre led to Chivington's resignation; Colorado's Second Territorial Governor, John Evans’, dismissal; and the U.S. Congress refusing the U.S. Army's repeated requests for a general war against the Plains Indians.

I think there is not much danger of my spoiling—our Col. is a Methodist Preacher and whenever he sees me drinking, gambling, stealing, or murdering he says, he will write to Mother or my sister Annie, so I have to go straight."

July 1864 –Silas[2] Soule was "...a great favorite with the men of his own military company..." and could express a "...devilish sense of humor..."being able to "...slither under the thickest skin of pro-slavery or Union supporter alike, with his sharp tongue, cynical nature and charming wit ... [being] wise beyond his years and able to separate the wheat from the chaff on matters of politics..."[2] On April 1, 1865, Soule married Thersa A.

Soule's large memorial stone was not moved with his remains, and he now has a soldier's gravestone in the Grand Army of the Republic section of Riverside Cemetery.