DNY59/iStock(DALLAS) — When Amber Guyger placed her key in the door of apartment No. 1478 at the South Side Flats apartment complex in Dallas, she set off a chain of events that cost an innocent man his life and ended her career as a police officer.A little more than a year after Guyger, 31, fatally shot Botham Jean when she mistook his apartment for her own apartment one floor below, prosecutors are asking a Texas jury to convict her of murder. But defense attorneys have countered that Guyger made a tragic and “reasonable mistake,” believing she’d interrupted an intruder in her own home and using lethal force to defend herself.Had he lived, Jean would have celebrated his 28th birthday on Sunday.Guyger’s trial resumed on Monday.Here is a timeline of events that led to days of protests in the streets of Dallas and calls for justice from Jean’s loved ones in the Caribbean nation of Saint Lucia:Sept. 6, 2018 — Botham Jean, an accountant at the international auditing firm PriceWaterhouseCoopers, is in his apartment eating ice cream when Guyger, who has just capped off a 13 1/2-hour shift as a Dallas police officer by helping a SWAT team arrest three suspected robbers, enters through his unlocked door and fatally shoots him in the chest after mistaking him for a burglar. Moments after the shooting, Guyger realizes she is in the wrong apartment.Sept. 9, 2018 — An arrest warrant is issued for Guyger, charging her with manslaughter. She is released on $300,000 bond and put on administrative leave from her job. Guyger, according to an arrest warrant affidavit, told investigators she arrived home from work about 10 p.m. and mistakenly parked her pickup truck on the fourth floor of the building instead of the third floor, which corresponded to her apartment. She claimed she then walked down a hallway to an apartment she thought was hers, but when she inserted the key she found the door was slightly ajar. As she entered the apartment she heard someone inside and saw a “large silhouette” in the nearly completely darkened apartment that she thought was a burglar. She fired twice after telling the person she believed to be an intruder to show his or her hands, authorities said.Sept. 11, 2018 — Lee Merritt, an attorney for Jean’s family, calls Guyger’s story “highly implausible.” Dallas County District Attorney Faith Johnson says she has not ruled out a murder indictment.Sept. 13, 2018 — Hundreds of friends, loved ones and work colleagues pack Jean’s funeral at the Greenville Avenue Church of Christ in the Dallas suburb of Richardson. Several busloads of students and former classmates of Jean from Harding University, a Christian liberal arts college in Searcy, Arkansas, where Jean graduated in 2016, also attend the service. “The sound of gunshots did not have the resonance to be heard on our small island, but their impact was of nuclear proportions,” Jean’s uncle, Ignatius Jean, who traveled from Saint Lucia, tells mourners. “A nuke had been unleashed on our family by someone charged to protect and serve.”Sept. 24, 2018 — Dallas Police Chief Renee Hall announces Guyger has been fired. Hall says her decision to terminate Guyger was made after an internal affairs investigation concluded that Guyger “engaged in adverse conduct” when she fatally shot Jean.Nov. 30, 2018 — A Dallas County grand jury indicts Guyger on one count of murder. “I truly believe that she inflicted tremendous evil on my son. He didn’t deserve it,” Jean’s mother, Allison Jean, tells reporters. He felt safe in that apartment and he was violated.” Guyger pleads not guilty.Jan. 20, 2019 — A woman who filmed the aftermath of the shooting of Jean claims in an interview that she has been receiving death threats and was fired from her job after she uploaded the video to social media. The footage shows an apparently distressed Guyger, still in her police uniform, talking on her phone as she paces back and forth outside Jean’s apartment on Sept. 6.April 30, 2019 — The 911 call made by Guyger after she shot Jean is obtained by ABC Dallas station WFAA. In the call, Guyger repeatedly tells a dispatcher, “I thought it was my apartment,” and says, “I’m going to lose my job.”Sept. 23, 2019 — Guyger’s murder trial begins in Dallas. Prosecutor Jason Hermus asks the jury to convict Guyger of murder, saying she gave Jean “no opportunity for de-escalation, no opportunity for him to surrender” before she opened fire, killing him. Defense attorney Robert Rogers accuses the prosecution of “making innocent mistakes into evil acts.” He says the “only justice, in this case, is to find Amber Guyger not guilty.”Sept. 24, 2019 — Jurors are shown the harrowing bodycam footage in court from inside the apartment complex that captured arriving officers’ confusion after the shooting. Guyger is seen directing officers to Jean’s apartment, telling them, “I thought it was my apartment. I thought it was my apartment.” At one point in the video, officers on the scene could be seen taking turns desperately trying to revive Jean as he lay unconscious on his living room floor.Sept. 25, 2019 — Texas Ranger David Armstrong, lead homicide investigator on the high-profile case, testified without the jury in the courtroom, saying that based on the investigation he doesn’t believe Guyger committed a crime when she shot Jean and that it was “reasonable” for her to “perceive him as a deadly threat.” Judge Kemp refuses to allow Armstrong to state his opinions in front of the jury, but defense attorneys say they plan to call him back to the stand as an expert witness.Sept. 26, 2019 — Guyger testifies in her own defense, telling the jury of the moment she came face-to-face with Jean after opening the wrong apartment door. “I was scared to death,” she testifies, adding that her “heart rate just skyrocketed.” Overcome with emotion, Guyger breaks down several times on the witness stand, telling the jury, “I’m so sorry. I never wanted to take an innocent person’s life.” She adds, “I wish he was the one with the gun that killed me.”Copyright © 2019, ABC Radio. All rights reserved.