A man who shot dead three people in a racially motivated attack in Florida wrote of his hatred of black people, police say.
Twenty-one year old Ryan Christopher Palmeter fired eleven rounds at one woman sitting in her car in Jacksonville, before entering a shop and shooting another two people.
Sheriff T K Waters said he then turned the gun on himself.
Mayor Donna Deegan said the attack was driven by racist hatred.
At a news conference on Sunday, Sheriff Waters confirmed the gunman had no previous criminal history and had lived with his parents in Clay County.
The three victims were identified as Anolt Laguerre Jr, 19, Jerrald De'Shaun Gallion, 29 and 52 year-old Angela Carr.
Mr Laguerre worked at the Dollar General store where the attack happened, the company said.
The gunman had written messages detailing his hatred of black people, police said.
"Finely put: this shooting was racially motivated and he hated black people." Sheriff Waters said.
"He knew what he was doing. He was 100% lucid," he added. "He knew what he was doing and again, it's disappointing that anyone would go to these lengths to hurt someone else."
Mr Waters said the gunman had been detained for 72 hours in 2017 under the Baker Act, mental health legislation that allows the involuntary detainment of an individual for treatment.
But the sheriff said his weapons had been acquired legally, telling reporters the problem was not with the availability of guns, but with the killer being "a bad guy".
He urged people not to "look for sense in a senseless act of violence".
Jacksonville police played CCTV video at the news conference showing the moment the attacker walked up to the car where he killed the first woman. It then cut to video of him entering the shop.
Mr Waters also confirmed that the gunman let some people out of the shop without injuring them.
"Why? I don't know. Some of them were white, but I do believe there was a couple that were not," he said.
US Attorney General Merrick Garland said on Sunday the Justice Department was "investigating this attack as a hate crime and an act of racially motivated violent extremism".
"No person in this country should have to live in fear of hate-fuelled violence and no family should have to grieve the loss of a loved one to bigotry and hate," he said.
The attack happened less than a mile from the historically black Edwards Waters University.
The gunman first went to the university campus, where he was asked to identify himself by a security officer, the university said in a statement. When he refused, he was asked to leave.
"The individual returned to their car and left campus without incident," the statement added.
Sheriff Waters said the gunman was then seen putting on a bullet-resistant vest and a mask before leaving the campus.
The university went into lockdown after the shooting.