BUFFALO, N.Y. (WIVB) — Erie County says a 911 dispatcher has been fired after hanging up on a call coming from inside the Tops store in Buffalo where prosecutors say a white gunman killed 10 Black people in a hate-based domestic terror attack.

The dispatcher had been placed on administrative leave, but the county was pushing for her firing. Last month, Erie County Executive Mark Poloncarz said her actions were “inappropriate” and “unacceptable.”

According to a report by The Buffalo News, the dispatcher asked why the caller, a Tops employee, was whispering, before hanging up on her.

The dispatcher’s union, the Civil Service Employees Association, said Thursday it had ensured that disciplinary due process provisions were “followed fairly and appropriately here.”

The dispatcher told The Buffalo News late last month she was sorry about what the caller went through during the shooting, adding that more facts would come out at the hearing. A message was left Thursday at a possible phone number for her.

The 18-year-old white gunman accused in the mass killing pleaded not guilty Thursday to hate-motivated domestic terrorism and other charges. A prosecutor called the evidence against him overwhelming.

A lawyer entered the plea for Payton Gendron, 18, in the first case to make use of New York’s domestic terrorism hate crime law. Gendron didn’t speak during the brief hearing with a heavy security presence.

Witnesses, police and Gendron’s own writings and livestreamed video have incriminated him as the gunman who used an AR-style semi-automatic rifle on May 14 to target shoppers and employees of a Tops Friendly Market, and he surrendered at the crime scene after putting his rifle to his neck. Authorities said he chose the store because of its location in a predominantly Black neighborhood.

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“There is overwhelming proof of the defendant’s guilt,” Assistant District Attorney John Fereleto said. “The defendant was caught at the scene of the crime with the weapon in his hands.”

Gendron has been held without bail since the shooting and is due back in court July 7.

He was charged with murder shortly after the attack. On Wednesday, a new indictment expanded the case to include the domestic terrorism charge, along with 10 counts of first-degree murder, 10 counts of second-degree murder as a hate crime, criminal possession of a weapon and three counts of attempted murder as a hate crime.

“When you hear the phrase ‘throw the book at’ someone, well, in this case right here, the defendant just got ‘War and Peace,’” District Attorney John Flynn said at a news conference after the arraignment.

The domestic terrorism hate crime charge — officially, domestic acts of terrorism motivated by hate in the first degree — was added to state law just two years ago, after a mass shooting targeting Mexicans at a Walmart store in El Paso, Texas. The offense carries an automatic life sentence upon conviction.

Until now, no arrests or arraignments or arraignments under the law have been reported to the state Division of Criminal Justice Services, spokesperson Janine Kava said.

In Gendron’s case, the charge accuses him of killing at least five people “because of the perceived race and/or color” of his victims.

Outside court, Buffalo Mayor Byron Brown called Gendron “a racist, hate-filled outsider who came to our community with the stated intent to kill as many Black people as possible.”

Prosecutors said Gendron drove about three hours to Buffalo from his home in Conklin, New York, to target African Americans. Shortly before opening fire, he posted documents that outlined his white supremacist views and revealed he had been planning the attack for months.

Federal authorities also are investigating the possibility of hate crime charges against Gendron.

The slain victims ranged in age from 32 to 86. Three other people were wounded.

The bloodshed, followed 10 days later by a mass shooting that killed 19 children and two teachers inside an elementary school in Uvalde, Texas, has renewed a national debate about gun control.

The Associated Press contributed to this report.