The case haunted Birmingham for years. Four black girls in Alabama had been killed in the 1963 bombing of the 16th Street Baptist Church — a crime that shocked the country and helped fuel the civil rights movement.

Yet the men responsible — members of the Ku Klux Klan who’d boasted about their role — were never tried and convicted. That changed in 1977 when Robert “Dynamite Bob” Chambliss, the suspected ringleader of the bombing, was put on trial.

At the time, Doug Jones, now a Democratic candidate for the U.S. Senate in a hotly contested race Alabama, was a second-year law student. He skipped classes to sit in on the trial, watching in amazement as William Joseph Baxley II, then Alabama’s attorney general, presented evidence against Chambliss....

More than 20 years after Chambliss was convicted, Jones would become U.S. attorney in Alabama and set out to finish what Baxley started. He brought charges against two more Klan members, Thomas Edwin Blanton Jr., and Bobby Frank Cherry....