During the process, relatives of the victims lower their gaze as the names of the dead are read out
Photo: Joshua Bessex/AP
The man, heavily armed, opened fire in front of and in a supermarket in mid-April – and was arrested at the scene: around six months after the allegedly racially motivated attack on black people in a US supermarket, the shooter pleaded guilty in court.
He had killed ten people and injured three others in his act in the city of Buffalo.
The 19-year-old gunman is charged in New York state with domestic terrorism and murder as hate crimes, among other things.
He faces a life sentence.
The investigators are assuming a racist motive on the part of the accused – eleven of the 13 victims were black.
A 180-page manifesto with racist and violent statements attributed to the accused had also appeared on the Internet.
The avowed racist had chosen a market for his attack in a predominantly black neighborhood in the city, in upstate New York, according to prosecutors.
He therefore drove three hours from his home near Binghamton, New York, to the supermarket after weeks of planning the attack.
He left a racist manifesto on the internet before the attack, police say, and live-streamed the shooting on social media.
"It has been established beyond a reasonable doubt that he had this grisly motive and murdered as many African Americans as possible in a little over two minutes," said John Flynn, the Erie County Attorney.
"Justice was served today." According to media reports, the verdict is scheduled for February 15.
The defendant, 18 at the time of the attack, initially pleaded not guilty after a grand jury returned indictments in June.
In the separate indictment, filed in another court under federal law, Gendron faces 27 counts of hate crimes and firearms offenses.
The penalties associated with the federal allegations are usually higher than those at the state level, and the death penalty would be a possibility.