On Thursday night, newly published interviews with those who knew alleged Charleston shooter Dylann Roof provided disturbing details about the man accused of killing nine people in a racially motivated attack yesterday.

In an interview with ABC News, roommate Dalton Tyler told the network that Roof had been “planning something like that for six months.” “He was big into segregation and other stuff,” Tyler told ABC. “He said he wanted to start a civil war. He said he was going to do something like that and then kill himself.”