The staccato rat-rat-rat of semi-automatic gunfire resounded in a federal courtroom Tuesday as a jury watched a video from outside the Tree of Life synagogue building in Squirrel Hill on Oct. 27, 2018. 

It sounded like a war zone because it essentially was — a rapid-fire shootout inside the building between the Pittsburgh police SWAT unit and mass killer Robert Bowers. 

Police had cornered Bowers in a dark top-floor classroom, where he opened fire on them with the AR-15 assault weapon he had already used to slaughter 11 innocent worshippers, wound two others and shoot a police officer in the hand.

SWAT Officer John Persin said memories of all he saw, heard and smelled that day still haunt him nearly five years later. 

“They invade my thoughts every day,” he told the jury. 

From his hiding place, Bowers shot SWAT members Tim Matson and Anthony Burke, forcing the team to retreat and execute a rescue of their comrades. 

Officers then engaged him in a second gunfight and wounded him. 

Video recorded from the street outside the building captured a furious exchange of high-velocity rounds. 

Persin said Bowers started the shooting. At one point, police needed to use a flash bang to distract him while they extricated Burke past the entrance of the killer’s refuge. 

But the operation didn’t quite go as planned. 

“The flash bang bounced off the doorway and hit me and detonated,” Persin said. “It stunned me.”

His hearing has never recovered fully. He said he can’t hear high-pitched sounds anymore — such as the voices of his children. His tinnitus is with him always. 

“It reminds me constantly, yeah,” he said. 

Persin was the last government witness to testify on Tuesday in the death penalty trial for Bowers, a trucker from Baldwin who, armed with four guns, rampaged inside the synagogue against helpless elderly victims as they prayed on a quiet Saturday morning. 

The government says he did it because he hates Jews. 

The defense does not dispute his actions. The lawyers’ only goal is to spare him from execution. 

The day began with testimony from another SWAT officer, Andrew Miller, who recounted Bowers shooting at him in the darkness, his bullets hitting drywall behind him and filling the air with particle dust. 

“He was just missing me,” he said of Bowers. 

Miller couldn’t see the shooter but fired at the muzzle flash of his gun as it moved across the back of the room in the blackness. 

“I didn’t want to get shot,” he said. “I didn’t want to die.” 

Matson, the first man into the room, had already been badly wounded. The team dragged him down the stairs to a safer place. Miller said Matson, wounded in the legs and the head, was screaming, “I’m f—ed up, man.”

After medics tended to Matson, Miller ran back upstairs to rejoin the fight against Bowers. 

Asked by a prosecutor why he took that risk, he had a simple answer: “It’s what we do. It’s what we train for.” 

After Bowers had been wounded and crawled out, Miller said he heard him say to another officer, “I had to do it. Jews are the children of Satan.” 

That quote and others like it are key to the government’s hate-crimes case because prosecutors must show specific intent. 

Testimony in between the two SWAT members took most of the day and focused on autopsies, which revealed that Bowers shot the congregants multiple times at close range, in some cases with the muzzle of his AR-15 pressed against their bodies.

Three pathologists testified about the victims they examined. 

One of the dead, 88-year-old Melvin Wax, had been shot with the rifle held directly against his chest.

The pathologists all noted that the AR-15 fires high-velocity rounds, up to three times faster than a typical handgun, resulting in catastrophic wounds. Many of the victims had been shot in the head, causing devastating injuries and instant death.

Police found their bodies strewn throughout the synagogue. 

Under questioning, the pathologists noted that the autopsies revealed most of the victims had been healthy. 

Rose Mallinger was one of them. 

Pathologist Ashton Ennis said she was in great health despite her age.

She was 97 when Bowers killed her.

Torsten covers the courts for the Pittsburgh Post-Gazette, but he's currently on strike. Reach him at jtorsteno@gmail.com.

Harrison, a rising senior at Denison University, is a Union Progress summer intern. Email him at hhamm@unionprogress.com.