Boston officials say a longtime firefighter has been placed on leave following a series of "disturbing" posts on social media. A spokesperson for Boston Fire said Octavius Rowe, a 15-year veteran of the department, was placed on paid leave Oct. 2. Fire spokesman Steve MacDonald says some of the posts are violent in nature. The Boston Fire Department said Tuesday one of the posts involved a cartoon man carrying a decapitated head with the caption "Nat Turner's slave rebellion." A police spokesman says no criminal behavior has taken place. Lieutenant Detective Michael McCarthy said a police officer has been stationed in front of fire headquarters "out of an abundance of caution." Fire officials and police are continuing to investigate.