During the years of 1855 and 1856 , tensions erupted into open warfare between proslavery and antislavery forces along the border . In May 1856 , a group of Missourians sacked the town of Lawrence , Kansas ; the town 's hotel , printing press , and several houses were destroyed , and several Kansans were killed . In response to the sacking , a group of Missouri settlers were attacked and massacred at Pottawatomie Creek in Kansas by John Brown and his group of abolitionists . In response to the killing , a group of Missourians known as the Westport Sharpshooters attempted to capture Brown , but they were themselves captured by him . In August 1856 , however , another group of proslavery Missourians invaded Kansas and burned the town of Ossawotamie , which was home to Brown 's headquarters
massacred at Pottawatomie Creek
Pottawatomie massacre
History of Missouri