https://www.theguardian.com/technology/2019/apr/16/facebook-allowed-violent-posts-by-man-charged-with-ilhan-omar-death-threat

Site took no action to remove posts by Patrick Carlineo alluding to violence against Muslims and US officials, until Guardian review

Facebook allowed a man charged with threatening to kill congresswoman Ilhan Omar to post violent and racist content for years, and took no action to remove his posts when he was arrested.