A childhood friend of the man accused of shooting dead nine people inside a black church in South Carolina said he told him a few weeks ago he had "a plan".
oey Meek, who alerted the FBI after recognising Dylann Roof in a surveillance camera image, said he was drinking vodka with him when he made the remark while he was railing against blacks.
Roof, 21, did not elaborate, but Mr Meek said he was worried and knew his friend had a .45 calibre Glock pistol in the boot of his car, which Roof told him he bought using birthday money from his parents.
Because of the way Roof was behaving, Mr Meek said he took the gun from the car and hid it in his house, just in case.
"I didn't think he would do anything," he said. But the next day, when Roof was sober, he gave it back.
Mr Meek's brother Jacob said he recalled that as they were driving to a lake on Wednesday, the day of the Charleston church massacre, Roof said he should be careful moving his backpack in the car because of the "magazines".
But Jacob Meek thought Roof was referring to periodicals - instead of a device that stores ammunition.
"Now it all makes sense," he said.
Joey Meek said they had been best friends in middle school, then lost touch for years until Roof reappeared a few weeks ago.
"All the sudden out of the blue, he started talking about race. He started talking about (black Florida teenager killed by a neighbourhood watch volunteer) Trayvon Martin," Mr Meek said.
"He said blacks were taking over the world. Someone needed to do something about it for the white race. He said he wanted segregation between whites and blacks. I said, 'That's not the way it should be'. But he kept talking about it."
Roof, said to have joined a prayer meeting inside the historic church before the murders, has been returned to South Carolina after being captured without resistance in neighbouring North Carolina.
He waived extradition from the state and was taken to a waiting police car wearing a bulletproof vest, with shackles on his feet and his hands cuffed behind his back, then put on a plane.
He is being held at a detention centre pending a bail hearing.
Roof spent nearly an hour inside The Emanuel African Methodist Episcopal Church in Charleston on Wednesday night before killing six women and three men, including the pastor, state senator Clementa Pinckney.
He was captured after a florist spotted his car in North Carolina, nearly four hours away.
Charleston police chief Greg Mullen would not discuss a motive for the massacre and city mayor Joseph Riley called it "pure, pure concentrated evil".
Stunned community leaders and politicians condemned the attack and US attorney general Loretta Lynch said the Justice Department had begun a hate crime investigation.
President Barack Obama, who personally knew the murdered pastor, said such shootings had to stop.
"At some point, we as a country will have to reckon with the fact that this type of mass violence does not happen in other advanced countries," he said.
Mr Pinckney, 41, was a married father of two who spent 19 years in the South Carolina legislature. He became the youngest member of the house of representatives when he was first elected as a Democrat at 23.
The other victims were identified as Cynthia Hurd, 54; Tywanza Sanders, 26; the Rev Sharonda Singleton, 45; Myra Thompson, 59; Ethel Lance, 70; Susie Jackson, 87; the Rev Daniel Simmons, 74; and DePayne Doctor, 49.
The shootings took out the heart of a community - civic leaders including three pastors, a regional library manager, a college enrolment counsellor, and a high school athletics coach - and left the historic church with just one living minister.
Roof had a criminal record, with court records show a pending misdemeanour drug case and a past misdemeanour trespassing charge. And he proudly displayed the flags of defeated white-ruled regimes, posing with a Confederate flag plate on his car and wearing a jacket with stitched-on flag patches from Rhodesia, which is now black-led Zimbabwe, and apartheid-era South Africa.
The shooting evoked painful memories of other attacks. Black churches were bombed in the 1960s when they served as organising hubs for the civil rights movement, and burned across the South in the 1990s. Others survived shooting sprees.
This particular congregation, which formed in 1816, has its own grim history: A founder, Denmark Vesey, was hanged after trying to organise a slave revolt in 1822, and white landowners burned the church in revenge, leaving parishioners to worship underground until after the Civil War.
This shooting "should be a warning to us all that we do have a problem in our society", said state congressman Wendell Gilliard, a Democrat whose district includes the church. "There's a race problem in our country. There's a gun problem in our country. We need to act on them quickly."
The attack came two months after the fatal shooting of an unarmed black man, Walter Scott, by a white police officer in neighbouring North Charleston, which increased racial tensions. The officer awaits trial for murder, and the shooting prompted South Carolina to pass a law, co-sponsored by Mr Pinckney, to equip police statewide with body cameras.
North Carolina florist Debbie Dills was hailed for her help catching Roof.
She was on her way to work when she saw a familiar black Hyundai next to her at a traffic light. She said her heart raced when she saw the driver: a white man with a pudding basin haircut, just like the photos of the suspect she had seen on the news.
Ms Dills called her boss, Todd Frady, who contacted a police officer he knew. That officer contacted the Shelby Police Department, whose officers captured Roof.