(CNN) -- A Dallas jury on Tuesday found former police officer Amber Guyger guilty of murder for fatally shooting her unarmed neighbor, Botham Jean, in his own apartment, which she said she mistook for hers.
The jury deliberated less than 24 hours. The verdict followed a trial that has captured national attention and sparked outrage.
Judge Tammy Kemp asked Guyger and her lawyers to stand as she delivered the verdict. "We the jury unanimously find the defendant, Amber Guyger, guilty of murder as charged in the indictment," Kemp read, as a shriek and hand clap could be heard.
"No outbursts," Kemp said before announcing a break until 2 p.m. ET.
With the murder conviction, Guyger, 31, now faces up to life in prison.
Jean's mother immediately threw both arms in the air, then quickly retracted them. Another woman who started to shout in praise was chastised by a court officer. Members of Jean's family sobbed. There were hugs among family members and prosecutors after the jury left the courtroom.
Guyger, her head down, wept at the defense table. Her mother broke down in the courtroom.
When the courtroom doors opened, applause and cheers erupted in the corridors. Some cried on hallway benches and shouts of "Guilty! Guilty!" and "Black lives matter!" could be heard.
Outside court later, S. Lee Merritt, an attorney for Jean's family, called the rare murder conviction against a police officer a "huge victory" not only for the victim's family but also "for black people in America."
"It's a signal that the tide is going to change here," he told reporters. "Police officers are going to be held accountable for their actions and we believe that will begin to change policing culture all over the world."
Another family attorney, Benjamin Crump, cited the names of numerous unarmed African-Americans who have died at the hands of police.
"For so many unarmed black and brown human beings all across America, this verdict is for them," he said.
The Jean family would have no comment until after testifying at the sentencing phase later Tuesday, the attorneys said.
Guyger, who is white, testified that after working long hours on September 6, 2018, she returned to her Dallas apartment complex and approached what she thought was her apartment. She noticed the door was partially open, and pulled out her service weapon and shot a figure inside in the dark. It turned out she was at the apartment directly above hers -- which belonged to the 26-year-old man Jean, who was black -- and she thought Jean was an intruder.
The jury began deliberations in the trial Monday.
'I wish he was the one with the gun'
In uniform but off duty, Guyger testified last week that she wanted to "find the threat" after hearing movement in her apartment. She saw a silhouette and and demanded to see his hands, she said. The person approached in a "fast-paced walk," she added, and she fired two shots at what she believed to be an intruder.
One bullet struck and killed Jean. Prosecutors said he had been relaxing in his apartment with a fresh bowl of ice cream shortly before the incident around 10 p.m. CT.
"I ask God for forgiveness, and I hate myself every single day," Guyger told the jury, her voice shaking. "I wish he was the one with the gun who had killed me. I never wanted to take an innocent person's life."
Guyger was distracted that night, prosecutors argued, texting with her married police partner, with whom she had sexual relations. They said she missed numerous signs in the hallway leading up to Jean's apartment indicating she was on the wrong floor.
Lead prosecutor Jason Hermus also hammered Guyger for entering the apartment rather than backing away and seeking cover or calling for assistance over her police radio. He also argued she did not render enough first aid to Jean.
Experts have been unable to determine Jean's exact position when he was shot. A medical examiner testified the bullet entered just above Jean's upper left nipple and traveled downward, damaging his heart and several other major organs before landing in his psoas muscle.
"When you aimed and pulled the trigger at Mr. Jean, shooting him in center mass exactly where you are trained, you intended to kill Mr. Jean," Hermus said.
"I did," Guyger said.
On the phone with a 911 operator that night, Guyger said 19 times she thought she had been in her apartment. Guyger said she performed a "little" CPR and a sternum rub on Jean.
Hermus pointed out she never used first aid supplies from her backpack. Guyger testified her mind was racing while on the phone with a 911 operator. She said it didn't cross her mind that she had first aid supplies.
Texas Ranger David Armstrong, the lead investigator, said in court last week -- while the jury was not in the room -- that he believed Guyger's actions were reasonable and that she did not commit murder, nor manslaughter or criminally negligent manslaughter. The judge would not allow him to offer his opinion before the jury.
Guyger was initially charged with manslaughter in September 2018, but a grand jury later indicted her on a murder charge. The Dallas Police Department fired Guyger.
The trial was laced with dramatic, emotional moments, as attorneys played graphic body cam footage of police trying to resuscitate Jean and read explicit sexual messages between Guyger and her police partner.
The castle doctrine and closing arguments
After six days of witness testimony, the prosecution and defense teams rested Monday morning, then presented two hours of closing arguments. Prosecutors leaned heavily on their emotional appeal, while the defense urged the jury to use discipline and focus on the law.
In a significant move, the judge allowed Guyger's attorneys to argue the so-called castle doctrine -- or stand your ground laws -- as part of their defense, since Guyger believed she was in her own apartment. Guyger's actions were reasonable, defense attorneys said, and any ordinary person could have made the same mistake in a similar situation.
Defense attorney Toby Shook urged jurors to look at the case "calmly" and not decide on emotion, sympathy, or public pressure. "But you have to use the discipline not to do that," he said.
"That's hard, especially in a case like this," he added. "You'll never see a case like this, that's so tragic. So tragic. It's hard to do as jurors. Who would not have sympathy for Botham Jean? Wonderful human being -- died in these horrible, tragic circumstances."
Prosecutors argued self-defense did not apply because Guyger was not in her home. She acted disproportionately, prosecutors said, and had less lethal options available, like using her stun gun or mace.
"Self-defense is an option of last resort. She killed him unreasonably and unjustifiably," said Hermus.
The self defense argument should apply to Jean, not Guyger, they said. "It's not her apartment. There was not force. It's not occupied. She doesn't need castle doctrine," said Assistant District Attorney Jason Fine. "No. This law is not in place for her, it's in place for Bo."
Hermus argued it was "absolutely unreasonable" that Guyger missed numerous signs, including a bright red doormat outside Jean's door, that she was at the wrong apartment.
Hermus, in closing arguments, walked up to Guyger in her seat, pointed and looked her in the eye, and urged the jury to tell her: "You will be held responsible for what you did and whether or not you want to accept responsibility, it will be forced upon you.
"And by God in Dallas County, Texas," he continued, "there will be a consequence for you walking in and shooting an unarmed, defenseless man."