What about his manifesto?
I don't think someone's rambling blog can be called a "manifesto" when his daily life contradicts it. His friend is black and in the South, that black friend has had many opportunities to see Dylann Roof around other blacks; how he acted, what he said about/around them. The friend swears that Dylann Roof never had a racist comment.
I can blog all I want about "the purity of the Arabian horse" but I can and do cross breed out my mares when I find a nice stallion of another breed. I can hold the ideal while not being slavish to it.
To the point, the two witnesses we have now of record have said that Roof's main target was a school with predominantly white kids; and that he changed his mind at that particular date and went to sit in a Bible study for an hour while he calmly waited for a cue to rise and shoot 3 male and 6 aging female Christians.
I'm saying he should be prosecuted for two hate crimes, given that he is almost certainly gay and the day before was the big shattering announcement from another southern Christian church that its leadership was not allowing gay weddings under their watch no matter what SCOTUS says in the next coming days. If he is gay and this was a reaction against Christians, we the general public have a right to know that. We need to at least rule it out before we all sing in unison "it was RACISM ONLY!" so a very uncomfortable topic doesn't have to be explored..