"Turn to Christ. God will forgive you."

Mass murderer Dylann Roof heard those words from family members of those he mercilessly shot to death less than two years ago during a Bible study at South Carolina's Emanuel African Methodist Episcopal Church, Christian News reported.

Roof, the then 21-year-old white supremacist, killed nine people in cold blood, including the senior pastor, state senator Clementa C. Pinckney. He confessed to have plotted the massacre in hopes of igniting a race war.

On Wednesday, Roof was formally sentenced to death by jurors at a court in Charleston, South Carolina.

In closing statements before the deliberation, Roof didn't ask for mercy or apologise, telling the jurors: "I still felt like I had to do it," the Associated Press reported.

Roof reportedly showed little emotion during the reading of the sentence, even refusing to make eye contact with those who spoke to him and offered their prayers and forgiveness.

Dan Simmons Jr. approached the killer of his father, church ministerial staff member Daniel Simmons, and told him: "I understand why you don't want to look at us, so I will speak to the spirit that possesses you.

"You don't have to look at me. But I see that spirit. I want you to think about that as I forgive for your act, for your actions. Know you have an opportunity to ask for forgiveness. Know that God will forgive you. ... If you choose to serve Him, you will have a better life."

Roof looked as if he heard nothing. But Simmons was undeterred.

"I know that you don't understand that, but God requires me to forgive you," he said. "He also requires me to plead and pray for you. And I do that."

Shirrene Goss, another grieving relative of one of the massacre victims, was not as amiable as Simmons. She confronted Roof and reminded him of the gravity of his sins.

"You, young man, are among the worst kind of evil," she said. "One day before your final earthly judgment, it's going to come to you, and you are going to realise you did not have to do this. And it's going to hit you hard."

Meanwhile, Bishop Robert Guglielmone of Charleston, South Carolina, said despite the heinousness of Roof's crimes, he should not be put to death, the Catholic Herald reported.

"We are all sinners, but through the Father's loving mercy and Jesus's redeeming sacrifice upon the Cross, we have been offered the gift of eternal life," Guglielmone said.

"The Catholic opposition to the death penalty, therefore, is rooted in God's mercy. The Church believes the right to life is paramount to every other right as it affords the opportunity for conversion, even of the hardened sinner," he added.