The punishment phase of Amber Guyger's murder trial began Tuesday afternoon, two hours after a Dallas jury found the former police officer guilty of murder.

The jury took only five hours to decide that Guyger, a white cop who shot her black neighbor Botham Jean when she mistook his apartment for hers, was guilty of murder. She was the first Dallas police officer to be convicted of murder since the 1970s and faces up to 99 years in prison.

The jury first heard from Jean's mother, Allison. Prosecutors walked her through several pictures of her son during various stages of his life. Allison Jean spoke fondly of her son's academic and extracurricular accomplishments as well as his commitment to his church.

After the judge read the guilty verdict around noon, Jean's sister sobbed while his mother raised her fists in the air and said, "God is good."

Guyger's mugshot was released Tuesday night. (Dallas County Jail)

Ben Crump, a lawyer for Jean's family said, "Nothing will bring Botham back, but today his family has found some measure of justice. What happened on September 6, 2018, is clear to everyone: This officer saw a black man and shot, without reason and without justification. The jury's thoughtful verdict sets a powerful precedent for future cases, telling law enforcement officers that they cannot hide behind the badge but instead will face justice for their wrongful actions."

Guyger was off duty but in uniform when she shot at Jean twice, hitting him in the chest. She had worked a shift lasting over 13 hours on the Dallas Police Department's crime response team that day and mistakenly parked on the fourth floor of the complex's garage.

TRIAL OF AMBER GUYGER, DALLAS EX-COP WHO SHOT, KILLED NEIGHBOR BOTHAM JEAN, MOVES TO JURY

Guyger lived on the third floor and Jean, a 26-year-old accountant from St. Lucia, lived in the apartment above hers.

Prosecutors said Jean was watching television and eating a bowl of ice cream in his living room when Guyger burst inside. Prosecutors said the trajectory of the bullets showed that Jean either was getting up from his couch or was cowering when Guyger fired her service weapon.

The shooting has attracted intense national scrutiny not only for the strange circumstances surrounding it but also because it was one in a series of shootings of unarmed black men by white police officers. The incident led to widespread marches, protests and calls for Guyger to be held accountable for Jean's death.

Guyger, a four-year veteran of the Dallas Police Department, initially was charged with manslaughter. Two months later, a grand jury indicted her on a murder charge.

Throughout the trial, Guyger's defense team framed the shooting as a "tragic but innocent" mistake.

Dallas County District Court Judge Tammy Kemp ruled Monday that the jury could consider the controversial "castle doctrine," a law that basically says a person's home is their castle and therefore a person has the right to defend it.

Legal analysts said that the trial's outcome hinged on whether the jury would believe Guyger's account that she made a mistake and that the mistake was reasonable.

During closing arguments, prosecutor Jason Fine with the Dallas County District Attorney's Office slammed Guyger for changing her story on the witness stand. He said the case "has to do with [Guyger] making an unreasonable decision that put her in the [defense seat] and Bo in the ground."

He added: "This case is all about what is reasonable and what is absurd."

"This case is about what is reasonable and what is absurd."
— Jason Fine, prosecutor with the Dallas County District Attorney's Office

Fine also brought up witness credibility and told jurors they had a duty to look past Guyger's time on the police force and judge her like they would any other defendant. He then picked apart her testimony.

On Friday, Guyger testified in her own defense. She openly wept after her attorney Toby Shook questioned her about the moments that led up to the shooting.

"I was scared to death," Guyger said, adding that her "heart rate just skyrocketed."

Guyger, who grew up in a suburb of Dallas, said she "never wanted to take an innocent person's life."

She also reenacted how she reached the apartment door she believed was hers, with her backpack, lunch box and police vest in her left hand and said she heard the sound of someone walking around inside. She testified that when she put the key into the lock she noticed the door was ajar. She then saw the silhouette of a figure and pulled out her gun and yelled, "Let me see your hands! Let me see your hands!"

"I was scared he was going to kill me," she testified.

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Throughout the trial, jurors heard from officers who raced to the scene that night and who tried to resuscitate Jean. They also listened to testimony from neighbors and an investigator about how common it was for people to wind up on the wrong floor of the South Side Flats complex where Guyger and Jean lived. They also heard the 911 call Guyger made after she shot Jean where she was heard repeatedly saying, "I didn't mean to."

Prosecutors said Guyger was distracted by a sexually explicit conversation she was having with her partner on the police force. They said she missed a series of signs she wasn't on the right floor of her apartment, including a different colored doormat and lighted numbers.