In 1844, local prejudices and political tensions, fueled by Mormon peculiarity, internal dissent, and reports of polygamy, escalated into conflicts between Mormons and "anti-Mormons" in Illinois and Missouri. Smith was arrested, and on June 27, 1844, he and his brother Hyrum were killed by a mob in Carthage, Illinois. Because Hyrum was Smith's logical successor, their deaths caused a succession crisis, and Brigham Young assumed leadership over the majority of Latter Day Saints. Young had been a close associate of Smith's and was senior apostle of the Quorum of the Twelve. Smaller groups of Latter Day Saints followed other leaders to form other denominations of the Latter Day Saint movement.