“We cannot have that in the courtroom,” Eagan said. “We must conduct ourselves appropriately because we are all better than that.”

Gendron, a 19-year-old White man, pleaded guilty in November to one count of domestic act of terrorism motivated by hate, 10 counts of first-degree murder, three counts of attempted murder and a weapons possession charge in the mass shooting at Tops Friendly Markets on May 14, 2022.

He is expected to be sentenced to life without the possibility of parole.

Gendron walked into the courtroom in an orange prison outfit, shackled around the waist and his hands in cuffs. During the hearing, he took off his glasses and began crying during the testimony from the victims’ families.

Buffalo Mayor Byron Brown is sitting in the front row of the courtroom next to Buffalo Police Chief Joseph Gramaglia. Family members of the victims have filled the courtroom, and as many as 17 are expected to give victim impact statements.

Gendron shot a total of 13 people, including 11 Black people and two White people, authorities said. All the victims killed were Black.

Prosecutors have argued the horror that unfolded both inside and outside the supermarket was rooted in Gendron’s racism toward Black people. Evidence included social media posts and a lengthy document written by Gendron, revealing he had planned the attack and visited the supermarket several times prior to the massacre.

Gendron posted he chose the Tops market as his target because it’s located in the 14208 ZIP code in Buffalo which is home to the highest percentage of Black people close enough to where he lived in Conklin, New York.

In the document, he attributed the internet for most of his beliefs and describes himself as a fascist, a White supremacist and an antisemite.

The shooter’s charges included the first use of New York’s terrorism motivated by hate charge since it became available in 2020 under state law.

On the federal level, Gendron faces 10 counts of hate crime resulting in death, three counts of hate crime involving bodily injury, 10 counts of use of a firearm to commit murder during and in relation to a violent crime, and three counts of use and discharge of a firearm during a violent crime, according to a criminal complaint.

Gendron’s motive for the mass shooting was to prevent Black people from replacing white people and eliminating the white race, and to inspire others to commit similar attacks,” a criminal complaint filed by prosecutors in the US Attorney’s Office for the Western District of New York stated.

Gendron pleaded not guilty to the federal charges, which carry the potential for the death penalty.

In December, Gendron’s attorneys said during a court hearing he would be willing to plead guilty to the federal charges if prosecutors agreed to remove the death penalty as punishment.

Massacre devastated community

The shooting traumatized the predominantly Black neighborhood of Masten Park on Buffalo’s east side. The area was a food desert and the Tops Friendly Markets was the only supermarket in the neighborhood.

On the afternoon of May 14, Gendron turned the community’s source of necessities into a crime scene.

Gendron was heavily armed and wore tactical gear – including a tactical helmet and plated armor, police said at the time. He also livestreamed his actions using a camera.

Using an illegally modified semi-automatic rifle, the gunman shot four people outside the grocery store – three of whom died. He continued the massacre inside the store, fatally shooting an armed security guard and eight others, six of whom didn’t survive.

Following the carnage, the supermarket closed for two months. But when it reopened, there was still a sense of fear.

The supermarket underwent renovations, returning with added safety and security measures, and a memorial for the shooting victims inside the store, the supermarket said last year.

The security measures included enhanced video monitoring systems, an emergency evacuation audio/visual alarm system, the installation of additional emergency exits and increased professional security both inside and outside the store.

CNN’s Mark Morales, Sonia Moghe, Ray Sanchez and Kristina Sgueglia contributed to this report.