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The Supreme Court has denied an appeal made by mass murderer Dylann Roof, who was convicted of killing nine people in a shooting at a Black church in 2015.

The court did not comment on the case in dismissing it.

DYLANN ROOF TAKES CHURCH SHOOTING APPEAL TO US SUPREME COURT

Roof was seeking a Supreme Court decision on handling disputes surrounding his mental health. 

Roof previously demanded evidence of his mental health be left out of his trial and fired his legal representation during sentencing. 

In this June 18, 2015, file photo, Charleston, South Carolina, shooting suspect Dylann Storm Roof is escorted from the Cleveland County Courthouse in Shelby, North Carolina.

In this June 18, 2015, file photo, Charleston, South Carolina, shooting suspect Dylann Storm Roof is escorted from the Cleveland County Courthouse in Shelby, North Carolina. (AP Photo/Chuck Burton, File)

In 2017, Roof became the first person in the U.S. sentenced to death for a federal hate crime. Authorities have said Roof opened fire during the closing prayer of a Bible study at the church, shooting into the crowd of those assembled. 

He was 21 at the time of the massacre.

A federal appeals court last year upheld Roof’s conviction and death sentence for the racially-motivated slaying of nine members of a Black South Carolina congregation, saying the legal record cannot even capture the "full horror" of what he did.

COURT UPHOLDS DEATH SENTENCE FOR CHURCH SHOOTER DYLANN ROOF

In this April 10, 2017, file photo, Dylann Roof enters the courtroom at the Charleston County Judicial Center to enter his guilty plea on murder charges in Charleston, South Carolina.

In this April 10, 2017, file photo, Dylann Roof enters the courtroom at the Charleston County Judicial Center to enter his guilty plea on murder charges in Charleston, South Carolina. (Grace Beahm/The Post And Courier via AP, Pool, File)

In his appeal, Roof's attorneys argued that he was wrongly allowed to represent himself during sentencing, a critical phase of his trial. 

Roof successfully prevented jurors from hearing evidence about his mental health, "under the delusion," his attorneys argued, that "he would be rescued from prison by White-nationalists — but only, bizarrely, if he kept his mental-impairments out of the public record."

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FILE- In this June 18, 2015 file photo, two Charleston police officers stand in front of the Emanuel AME Church in Charleston, S.C. The trial for Dylann Roof, a white man accused of killing nine black people at the church, started Wednesday, Dec. 7, 2016, at the federal courthouse in Charleston, SC. (AP Photo/Stephen B. Morton, File)

In this June 18, 2015 file photo, two Charleston police officers stand in front of the Emanuel AME Church in Charleston, South Carolina. (AP Photo/Stephen B. Morton, File)

Roof, 28, is currently being held under maximum security in a Terre Haute, Indiana prison. He is on federal death row and awaiting execution.

The Associated Press contributed to this report.