Feds believe that Dylann Roff was 'self-radicalized' in the months before the attack in which he shot nine black churchgoers in Charleston last year.<br />The information filed Monday was part of a list of more than a dozen expert witnesses that prosecutors intend to call in Dylann Roof's federal death penalty trial later this year.<br />The government believes that Roof's actions were "consistent with the concept of leaderless resistance and martyrdom advocated by white supremacy extremist groups and self-radicalization leading to violence."
