South Carolina church shooting suspect Dylann Roof is due to make his first court appearance.
Dylann Storm Roof, 21, is suspected of shooting dead nine people at the Emanuel AME Churche in Charleston.
He was detained more than 200 miles away in North Carolina and flown back to Charleston.
Police are treating the killings as a hate crime.
Prayer vigils have been held in churches in Charleston and across the US for the six women and three men who died in the June 17 shooting.
Hundreds gathered outside the Emanuel AME Church, where the attack took place, to pay tribute.
Dylann Roof is due to appear in court via video link for a bail hearing on June 19. He is being held at a detention centre in the Charleston area, the county sheriff’s office said.
He was detained on June 18 after police acting on a tip-off stopped his car in Shelby, North Carolina. He waived his right to extradition and was flown back to South Carolina.
Police had earlier released CCTV images of the shooting suspect and the dark saloon car he had driven away in.
Dylann Roof’s social media profile suggests he was interested in white supremacy.
His Facebook page shows a picture of him wearing a jacket with flag-patches from apartheid-era South Africa and Rhodesia – the name of Zimbabwe during the era of white minority rule. He also had Confederate flag plate on his car.
Dalton Tyler, who said he was a friend of Dylann Roof, told ABC News the suspect had spoken in support of racial segregation and had said “he wanted to start a civil war”.
It emerged on Thursday that Dylann Roof had sat in a Bible study group at the church for nearly an hour before launching his attack.
“The suspect entered the group and was accepted by them, as they believed that he wanted to join them in this Bible study,” Charleston County Coroner Rae Wilson said.
She said he then became “very aggressive and violent”.
Eight people died at the scene and one person died later in hospital. There were three survivors.
The victims were named as Pastor Clementa Pinckney, 41; Cynthia Hurd, 54; Tywanza Sanders, 26; Ms Singleton, 45; Myra Thompson, 59; Ethel Lance, 70; Susie Jackson, 87; the Rev Daniel Simmons Sr, 74; and DePayne Doctor.
President Barack Obama said the killings again raised the issue of US gun ownership, saying: “At some point, we as a country have to reckon with the fact that this type of massacre does not happen in other advanced countries.”
The Emanuel church is the oldest African Methodist Episcopal (AME) church in the US south. Civil rights leader Martin Luther King gave a speech there in April 1962.