CHARLESTON, S.C. -- Dylann Roof had a “cold and hateful heart” when he pulled a pistol from his fanny pack during a Bible study last year and killed nine black church members as they closed their eyes for a final prayer, a prosecutor said Wednesday.

As the 22-year-old white man’s death penalty trial began, his lawyer conceded that Roof committed the slayings. But the defense suggested that he should be spared the death penalty.

Prosecutors said Roof sat in the church basement for about a half-hour with 12 parishioners of the Emmanuel African Methodist Episcopal Church before opening fire in an attempt to start a race war. One of the victims, the Rev. Clementa Pinckney, who was also a state senator at the time, had handed Roof a Bible to study during their session.

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“He pulled the trigger on that Glock .45 more than 70 times that night. More than 60 times he hit parishioners,” Assistant U.S. Attorney Jay Richardson told jurors during his opening statement.

“He seemed to them to be harmless. Little did they know what a cold and hateful heart he had,” Richardson said.

Roof faces 33 federal counts, including hate crimes, in the June 17, 2015, slayings. After the racially mixed jury determines Roof’s guilt, the federal trial will move to the penalty phase, where Roof plans to act as his own lawyer to apparently fight for his life.

Three people survived the shooting, including Polly Sheppard. As Roof approached her, he said “he would leave her alive to tell his story,” Richardson said.

A survivor of the massacre testified Wednesday that her Bible study group had just closed their eyes and started praying when a loud sound shattered the stillness. The basement room went dark.

When Felicia Sanders opened her eyes, she saw a young white man the parishioners had welcomed to the study only a half-hour earlier. Dylann Roof was mowing down the pastor and eight others with gunfire and hurling racial insults.

Sanders, the first witness in Roof’s death penalty trial, fought back tears as she recalled sheltering her granddaughter under a table and telling her to play dead. She watched in horror as her son Tywanza and her 87-year-old aunt, Susie Jackson, were killed in the fusillade.

At one point, she looked across the courtroom toward Roof and called him “evil, evil, evil.”

One of three survivors, Sanders said Roof came by the Wednesday night gathering and was given a study sheet and a Bible by the Rev. Clementa Pinckney, the church’s pastor and a state senator.

When she heard the loud noise, she assumed something was wrong with the electricity. Then she saw the real reason.

“I screamed he had a gun,” she said. But by that time, Pinckney had already been shot. Soon her son was hit.

“I watched my son come into this world and I watched my son leave this world,” she said before becoming so distraught that U.S. District Judge Richard Gergel called a recess. Several people sitting among the survivors’ family members and several jurors dabbed away tears.

Jurors will hear Roof’s confession and a manifesto in which he urged a race war, the prosecutor said. He hurled racial insults during the massacre, telling the parishioners he was killing them because he wanted a war between whites and blacks because blacks were raping white women and taking over the country.

Roof’s “racism, his violence, his assault on a house of worship won’t prevail in this courtroom,” the prosecutor said.

Roof, wearing a gray striped prison jumpsuit, stared down at the table in front of him. Defense attorney David Bruck said the facts of the case are largely undisputed and that he would likely ask few questions of the government witnesses. He may not call any witnesses of his own.

The defense has said repeatedly in both federal court and state court - where Roof faces another death penalty trial next year - that Roof is willing to plead guilty if capital punishment is taken off the table. Prosecutors have refused.

Bruck urged jurors to pay attention to the little things and use their common sense to try and figure out what made Roof hate black people so much. He tried to hint at reasons why Roof shouldn’t be put to death, but prosecutors loudly objected, saying that was for the penalty phase. U.S. District Judge Richard Gergel agreed.

Prosecutors showed pictures of each victim on video monitors throughout the courtroom, describing them in a few sentences. Several people sitting in seats reserved for the victims’ families dabbed away tears or held their heads in their hands.

Roof’s trial began as another one with racial overtones ended in a mistrial. Jurors couldn’t agree on a verdict for former North Charleston police officer Michael Slager, who shot a black man in the back as he was running away from a traffic stop. A bystander recorded the shooting and it was seen widely on TV and online.

The church slayings took place a little more than two months after the Slager shooting, and Charleston has stayed mostly calm, unlike other cities where police shootings and perceived racial injustice has rocked communities.

State prosecutors plan to retry Slager.