From the moment the trial of former East Pittsburgh police officer Michael Rosfeld got underway, it was clear that the case will focus on his state of mind when he shot and killed an unarmed black teenager, Antwon Rose, last summer.

Rosfeld stands accused of crimnial homicide in the trial, which began Tuesday morning in the Allegheny County Courthouse courtroom of Common Pleas Judge Alexander Bickett. And prosecutors urged the jury to focus on what Rosfeld could have known about Rose, and the threat he posed, when he pulled the trigger as Rose fled.

“I don’t think there’s going to be a serious dispute that Michael Rosfeld hit Antwon Rose on vital parts of his body," said deputy district attorney Dan Fitzsimmons, who is prosecuting the case. "I don’t think there’s going to be a serious dispute that Antwon Rose died as a result of those wounds."

The only thing that matters, he said, is “what Michael Rosfeld knew at the time he pulled the trigger.”

By contrast, defense attorney Patrick Thomassey urged jurors to look at a bigger picture. He called the area where the drive-by took place a “crime gallery," in an area where drive-by shootings were common. "This is the type of area that Mike Rosfeld had to patrol every day.”

Rosfeld had pulled over a car he suspected of having been involved in a drive-by less than 15 minutes before, and Thomassey stressed that in such circumstances, “Police officers have different rules than we do. They have to." Stressing both their training they get and the risks they face, he said, “You hesitate, you die. You have to make split-second decisions.”

The trial began nine months to the day after Rose died of gunshot wounds around 9 p.m. on June 19. Rosfeld, who is white, shot Rose as he ran from the car the officer pulled over. Rose was unarmed and another teenager in the car, Zaijuan Hester, later pleaded guilty to being the shooter in the earlier incident.

After opening arguments Tuesday morning, jurors heard from a half dozen prosecution witnesses. Among them were two eyewitnesses to the shooting itself.

Debra Jones, whose house is directly adjacent to the site of Rose’s death, was the first eyewitness to take the stand. She said, watching from her front porch, she saw Rosfeld pull over the car Rose was in.

“[Rosfeld] was talking to [Rose] rough,” she recalled. When Rose and Hester fled the car, she said, Rosfeld did not call out a warning or demand them to stop. Instead, she said, she “automatically [heard] ‘boom, boom, boom,’ three shots.”

Jones remembered seeing a deceased Rose lying face-down and handcuffed in a yard next to her house. Meanwhile, she said, Rosfeld "was red and very upset, and he was crying."

Thomassey asked Jones about a police report from the night of the shooting that said the witness appeared to be intoxicated about an hour after the shooting. Jones said she had not been drinking at the time of the shooting but had whiskey afterward, as she discussed the event with her neighbors.

Lashuan Livingston also testified Tuesday. Using her iPhone, she filmed the East Pittsburgh shooting from the porch of her second-floor apartment, which Thomassey said was about 60 yards away. She later posted the video to Facebook, which attracted the attention of local activists who protested the shooting for weeks last summer.

Livingston said she was alarmed when Rosfeld pointed the gun at the vehicle Rose was in and spoke with a “harsh” tone of voice.

“I had a bad feeling,” Livingston remembered. “And as soon as I pulled my phone out is when the officer let out fire, let out shots.”

Also testifying Tuesday was Abdulrezak Al-Shakir, a forensic pathologist from the Allegheny County medical examiner’s office. Al-Shakir discussed the gunshot wounds sustained to Rose’s face, arm, and his trunk, the last of which caused his death. He said there was no evidence of alcohol or drugs in Rose’s blood, he said.

Brian Hodges, a North Braddock police sergeant, testified about his presence at the scene of the drive-by shooting, and at the shooting itself. Hodges said that shortly after he arrived at the drive-by, Rosfeld and another East Pittsburgh officer arrived, then went in search of the car they suspected of being involved.

Allegheny County homicide detective Thomas Foley spoke about the investigation of the drive-by shooting, which took place in North Braddock. He discussed video of the incident that showed a backseat passenger firing from the car. Prosecutors have said that Rose sat in the front passenger seat of the car and didn’t fire shots.

Officer Anthony Perry, of the Allegheny County Police, then reviewed the scene of the shooting in East Pittsburgh, where Rosfeld killed Rose. Using photographs, he showed where four eyewitnesses had been located.

Hearing the case was a jury selected from Dauphin County last week. The defense had asked for an out-of-county jury, arguing that media coverage of Rose’s death and subsequent protests would compromise a local jury’s ability to review the facts fairly.

Those jurors looked attentive, some taking notes, throughout the morning. But in the gallery, there was audible weeping from the area where Rose’s family was seated when evidence, including photographs, of Rose’s gunshot wounds were discussed. Some family members left the courtroom.

Raw feelings were also on display outside the courtroom. Street trees outside the courthouse were bedecked with purple roses in memory of Rose, placed by activist group Bend the Arc. In a statement, the group said the display was an attempt “to ensure that Rose’s family and community feel the same outpouring of love and support that the Pittsburgh Jewish community receive after the October 2018 Tree of Life Synagogue massacre.”

Activists also carried a portable shrine which featured a painting of Rose surrounded by flowers.

After Tuesday’s hearing, Antown Rose’s mother, Michelle Kenney, appeared outside the courtroom with supporters, including her family’s attorney, Lee Merritt.

“We are encouraged that the prosecution will continue to pursue the facts of the case that matter. We feel that’s what they’re lying out methodically,” Merritt said. “But what we most want to see as a family, as a community is that Antwon Rose is introduced to this jury as if his life mattered.”

David Harris, a University of Pittsburgh law professor and 90.5 WESA legal analyst, likened opening arguments to “looking at the top of the jigsaw-puzzle box before you start the puzzle.”

“The jury’s going to hear the story through the witnesses, in pieces,” he told 90.5 WESA’s The Confluence, “so this gives the jury to chance to see the whole thing” as each side presents it.

Harris also noted that the case itself was part of a larger whole – a handful of high-profile police shootings in which circumstances were murky and the victims were black men. Thomassey himself is a familiar figure in that history, having defended a Brentwood police officer accused in the 1995 death of black motorist Jonny Gammage.

“This will be another landmark on Pittsburgh’s landscape,” Harris said. “This is part of the sweep over the past few decades.”

Chris Potter contributed. This report has been updated as trial proceedings have continued.