Dylann Roof is guilty of murder.

During a prayer service at Emanuel African Methodist Episcopal Church in Charleston, South Carolina, Roof killed nine African Americans worshipers. Roof was quickly identified as the main suspect, and became the focus of a massive manhunt that ended quickly with his arrest in North Carolina. He later confessed that he committed the shooting in hopes of igniting a “race war.”

Roof was convicted of 33 charges, nine of them involving hate crimes. Jurors began deliberating shortly after 1 p.m. on Wednesday. After about two hours they asked to review some evidence and came back within minutes with their verdict.

The next question is whether the jury will give Roof the death penalty. The penalty phase of the trial is set to begin on Jan. 3.

Are there some people that are just so evil that the death penalty is the only option? The death penalty has been on a steady downward curve since it reached a high of nearly 80 percent of Americans supporting it in 1994, according to Pew Research Center.

However, as W. James Antle III wrote in The Week, “Some crimes are so heinous; there is no other just punishment for them.”

Antle wrote that Roof is the posterchild for the death penalty. He confessed to killing nine people praying is an historic church. The execution-style killings were premeditated and displayed a “burning in his (Roof’s) heart.”

Antle wrote many of the common objections to the death penalty do not apply in Roof’s case. There is no doubt about his guilt. “I went to that church in Charleston and I did it,” Roof confessed with a laugh. “Did you shoot them?” a law enforcement officer asked. “Yes,” Roof replied, laughing again.

In the past, when support for the death penalty hovered at the mid-60 percent support, survey participants, when asked about specific cases like Timothy McVeigh or Saddam Hussein, support for executions rose above 80 percent.

In my book, “The Executioner’s Toll, 2010,” I wrote about a condemned inmate who cried out for the death penalty — literally — and deserved it as well.

John David Duty was in an Oklahoma penitentiary serving three life sentences after being convicted of armed robbery, kidnapping, first degree rape and shooting with intent to kill. It was December 2001 and Duty decided he that he had served enough time in prison, he and been in prison since 1978, and at the age of 49 he was not prepared to spend another 30 years in prison.

Duty did not try to escape or even commit suicide. He decided he would murder his cellmate, ask for the death penalty and have the state of Oklahoma put an end to his miserable existence in the state penitentiary system.

Duty’s diabolical plan involved treachery, murder and the heartless effort to compound the suffering of his victim’s family.

About an hour after killing his cellmate Curtis Wise, Duty sat down and wrote a cold blooded letter to Wise’s mother.

The letter included the following: “Well by the time you get this letter you will already know that your son is dead. I know now because I just killed him an hour ago.”

At some point after the murder, Duty wrote a second letter, this one to the district attorney’s office. He told the DA if you don’t execute me, “you’re only telling me it’s ok for me to kill again … Only next time it will be a guard or staff member.”

The death penalty was the only way to keep Duty from killing again. Support for the death penalty may be waning but it still has utility in some cases.

— Matthew T. Mangino is of counsel with Luxenberg, Garbett, Kelly & George P.C. His book, “The Executioner’s Toll, 2010,” was recently released by McFarland Publishing. You can reach him at mattmangino.com and follow him on Twitter at @MatthewTMangino.