PITTSBURGH — A Pittsburgh police tactical officer who was among the first law enforcement members to get inside the synagogue building during a shooting three years ago that killed 11 people told a judge Tuesday that defendant Robert Bowers made several references to killing Jews.

Officer Stephen Mescan was the first to testify in what is expected to be a two-day hearing into whether prosecutors will be allowed to use at trial certain statements made by Bowers the day of the October 2018 massacre.

Federal prosecutors played dozens of snippets from police radio transmissions from the scene, including one in which Mescan said: "Suspect is talking about ‘all these Jews need to die.’" Mescan told U.S. District Judge Donetta W. Ambrose that Bowers made other similar statements that day.

Bowers, who faces more than 60 federal charges, including hate crimes violations, obstruction of religious belief and the use of a firearm during a crime of violence, was not in the Pittsburgh federal courtroom Tuesday. He has pleaded not guilty and faces a possible death penalty if convicted.

GEORGIA MEN FACING HATE CRIME CHARGES IN SHOOTING DEATH OF AHMAUD ARBERY TO STAND TRIAL EARLY NEXT YEAR

In this Oct. 27, 2019 file photo a man places an American flag outside the Tree of Life synagogue in Pittsburgh on the first anniversary of the shooting at the synagogue, that killed 11 worshippers. An evidentiary hearing in the case of Robert Bowers a western Pennsylvania truck driver accused of killing 11 people at the Pittsburgh synagogue in 2018, is expected to get underway inside a federal courtroom in Pittsburgh on Tuesday. (AP Photo/Gene J. Puskar, File)

Authorities allege Bowers, 49, of Baldwin, Pennsylvania, perpetrated the deadliest attack on Jews in U.S. history. He also wounded seven, including five police officers, at the Tree of Life synagogue.

Investigators say Bowers opened fire with an AR-15 rifle and other weapons during worship services inside the building, killing eight men and three women. He was arrested after a police tactical team tracked him down and shot him.

Three separate congregations — Tree of Life, Dor Hadash, and New Light — were conducting Sabbath services in different areas of the large building in Pittsburgh’s Squirrel Hill neighborhood when the attack happened.

CLICK HERE TO GET THE FOX NEWS APP

Mescan said that when he and other tactical officers entered the building, they saw to their right two victims who had been shot in the head several times, and a trail of blood leading to the building's basement.

The hearing is expected to last all day and continue Wednesday.