Dylann Roof, the white supremacist who shot and killed nine black parishioners in Charleston, said he did "not shed a tear for the innocent people I killed".
Appearing in South Carolina's Federal District Court on Wednesday (4 January), the 22-year-old offered no apology, no explanation and no remorse for the massacre, which took place in June 2015.
Instead, as Roof addressed his jurors in court for the very first time, he insisted he was not mentally ill.
Roof, who sidelined his defence to represent himself, told the jury he was "not going to lie" to them, adding that, "there's nothing wrong with me psychologically," reported the New York Times.
The jury of 10 women and two men must decide whether Roof will be given the death sentence or life in prison without parole, after finding him guilty of 33 counts in December.
For Roof to be sentenced to death, all 12 jurors must be unanimous in their decision.
Assistant US Attorney Nathan Williams argued that Roof's crimes were awful enough to deserve the ultimate penalty.
During his opening statement, Williams read from a journal that Roof kept in the weeks after he was imprisoned for his actions.
In the journal, Roof said: "I would like to make it crystal clear I do not regret what I did," later adding, "I am not sorry".
Roof, who was then 21, also wrote: "I do feel sorry for the innocent white children forced to live in this sick country and I do feel sorry for the innocent white people that are killed daily at the hands of the lower race.
"I have shed a tear of self-pity for myself. I feel pity that I had to do what I did in the first place. I feel pity that I had to give up my life because of a situation that should never have existed."
The hearing is expected to proceed into next week, as the prosecution will call over 30 witnesses to demonstrate Roof's remorselessness.