When is a Crime a Hate Crime?

When is a Crime a Hate Crime? | The Marshall Project:
Dylann Roof and the challenges of proving bias.
When a white gunman opened fire at South Carolina’s historic Emanuel African Methodist Episcopal Church on Wednesday night, killing nine African-American worshippers, Charleston Police Chief Greg Mullen said, “we believe this is a hate crime; that is how we are investigating it.”
Attorney General Loretta Lynch likewise announced the Department of Justice had opened a hate crime investigation.
But “‘hate crime’ is a term that means something legally different than it’s used publicly,” says Barry Kowalski, a recently-retired lawyer with the Department of Justice’s Civil Rights Division, which is responsible for these prosecutions.
To prove a hate crime, prosecutors must prove not only that someone committed a particular crime, but also why: in this case, a jury would have to believe beyond a reasonable doubt that Dylann Roof killed nine people and that his actions were motivated by racial animus.
In the Charleston case, this seems like a relatively straightforward proposition:
The shooter didn’t just target a historically black church with a rich history of African-American activism.
He allegedly said, in the course of his attack, “I have to do it.
You rape our women and you’re taking over our country. And you have to go.” It’s unusual that the motive is stated so clearly at the time of the crime, however.
In cases where the motivation is less obvious, prosecutors must cast a wider net for proof: 
“Does the guy belong to a hate group? Can we get a search warrant for his computer? Did he say anything either immediately before or immediately after the crime? What is his connection to these victims?” says Bill Fitzpatrick, the Syracuse, NY District Attorney and President-Elect of the National District Attorneys Association...