Originally Published: 05 DEC 22 07:30 ET

Updated: 05 DEC 22 11:47 ET

By Ray Sanchez, Ashley Killough and Eric Levenson, CNN

(CNN) -- The former Fort Worth police officer who fatally shot 28-year-old Atatiana Jefferson in her own home in 2019 did not see her holding a gun in the split-second before firing at her through a back window, prosecutors said in opening statements of his murder trial Monday.

"This is not a circumstance where they're staring at the barrel of a gun and he had to defend himself against that person or to protect his partner," Tarrant County prosecutor Ashlea Deener said. "The evidence will support he did not see the gun in her hand. This is not a justification. This is not a self-defense case. This is murder."

Yet the defense attorney for former officer Aaron Dean said he had seen an armed silhouette with a green laser pointed at him and later found a firearm lying next to her body.

"In that window he sees a silhouette," attorney Miles Brissette said. "He doesn't know if it's a male or female, he doesn't know the racial makeup of the silhouette. He sees it, he sees the green laser and the gun come up on him. He takes a half-step back, gives a command and fires his weapon."

The contrasting opening statements come at the start of a trial which will feature fraught issues of race, police violence, gun rights and body-camera footage.

Dean, who is White, has pleaded not guilty to murder for killing Jefferson, who is Black, after firing into her home in October 2019 in front of her young nephew. The charge carries a possible sentence of 5 to 99 years.

Jury selection ended Friday. Eight men and six women were chosen, according to the Fort Worth Star-Telegram.

Judge George Gallagher has issued a gag order for the trial, which is expected to last two weeks.

Opening statements are scheduled during an abbreviated court day on Monday, so people can attend the funeral of lead defense attorney Jim Lane, who died suddenly in late November.

What happened the night of the shooting

Police responded to Jefferson's house around 2:25 a.m. on October 12, 2019, after a neighbor reported her doors were open in the middle of the night. The neighbor called a non-emergency police number to ask for a safety check at Jefferson's house.

Deener, the prosecutor, emphasized Dean and his partner did not at any point identify themselves as police when scoping out Jefferson's home. Jefferson took out her own gun because she heard noises outside and saw a flashlight in her backyard.

"She had no idea it was someone who was supposed to serve and protect," Deener said.

Brissette, the defense attorney, said the officers were treating the situation like a potential robbery in-progress and not, as has been previously reported, a welfare check, so they did not announce their presence. He described the shooting as a "tragic accident" but one that was "reasonable" for a person in Dean's position.

Heavily edited body camera footage showed an officer peering through two open doors, but he didn't knock or announce his presence. Instead, he walked around the house for about a minute.

Eventually, the officer approached a window and shined a flashlight into what appeared to be a dark room.

"Put your hands up! Show me your hands!" the officer yelled before firing a single shot, according to the body camera footage. He did not identify himself as police at any point in the video.

In the video, glare from the officer's flashlight makes it difficult to see anyone in the window.

Jefferson was pronounced dead minutes later.

Her nephew would later tell an investigator his aunt, after hearing noises outside, had taken out a handgun from her purse and pointed it toward the window, police said.

Jefferson had been playing video games with nephew

The shooting was widely condemned, with the National Black Police Association saying in a statement the killings of Black citizens by White officers had "reached critical mass."

Fort Worth Mayor Betsy Price at the time said Jefferson's killing was unjustified and "unacceptable."

Police initially said the officer fired his gun after "perceiving a threat." Officers provided medical care after the shooting, according to police.

Police said officers found a firearm when they entered the room where Jefferson died. Video released by police showed two mostly blurred clips, which appeared to show a firearm inside the home.

Dean, 34 at the time of the shooting, was hired in August 2017 and commissioned as a licensed officer in April 2018, police said.

Two days after the shooting, Dean resigned from the police force and was arrested and charged with murder, the crime for which he was indicted in December 2019.

The day after Dean's arrest, Lane told CNN his client "is sorry and his family is in shock."

Jefferson was trying to protect her nephew from what they both thought was a prowler, according to an attorney for Jefferson's family.

She had moved into her ailing mother's Fort Worth home a few months earlier to take care of her, family attorney S. Lee Merritt said at the time. She also took care of her nephews.

The night of the shooting, Jefferson stayed up late to play video games with her nephew. They played Call of Duty into the wee hours and left the door open to enjoy the crisp autumn air after weeks of searing heat, according to Merritt.

Jefferson graduated from Xavier University of Louisiana in 2014 with a degree in biology and worked in pharmaceutical equipment sales, according to her family's attorney.

The premed graduate, known as "Tay," was eulogized as a loving, caring and dependable aunt who accomplished many things in life.

Her nephew, Zion Carr, who witnessed the shooting, suffers from post-traumatic stress disorder, Merritt said. Since her death, family members said they have struggled to watch videos of other police killings.

Jefferson's father, Marquis Jefferson, suffered cardiac arrest and died in November 2019, just weeks after Dean fatally shot his daughter. He was 59.

Jefferson's mother, Yolanda Carr, died at her home in Fort Worth in January 2020 after becoming ill, according to Merritt. Carr had been ailing and couldn't attend her daughter's funeral.

Instead, the Rev. Jaime Kowlessar read a letter from Carr at the service.

"You often said you were going to change the world," Carr wrote. "I think you still will."