Fired Dallas police officer Amber Guyger appeared in court Thursday, her first time before the judge who will oversee her murder trial in the shooting death of Botham Jean.

During a 12-minute hearing, state District Judge Tammy Kemp quizzed attorneys about the leaking of Guyger's 911 call after the shooting despite a gag order. In the call, Guyger sounds frantic about shooting Jean but also repeatedly mentions that she is going to lose her job as a police officer.

Amber Guyger killed Botham Jean at the South Side Flats Apartments, blocks from Dallas police headquarters.

Guyger, 30, was off-duty but in uniform Sept. 6, 2018, when she killed Jean in his Cedars apartment, a block from Dallas police headquarters.

She told authorities she mistook Jean's fourth-floor apartment for her own — which was directly below his — and thought the 26-year-old accountant was a burglar. She said his door was unlocked and ajar, though Jean's family has questioned that account.

Jean, a native of St. Lucia, was watching football on his couch when Guyger arrived. She shot him once in the chest.

Guyger sat ramrod straight during the proceedings at the Frank Crowley Courts Building just outside downtown Dallas. She did not speak. Before the hearing began, she whispered "excuse me" to a man standing in the courtroom aisle who was preventing her from heading to the defense table.

Kemp had previously asked the prosecution and defense to question everyone they worked with about whether they released the 911 recording. She asked the attorneys for the results of the inquiries Thursday in court.

Fired Dallas police officer Amber Guyger appeared in court Thursday for the first time before state District Judge Tammy Kemp, who will preside over her murder trial. Guyger is charged with murder in the Sept. 6 shooting death of Botham Jean in his apartment. (Ryan Michalesko / Staff Photographer)

Kemp said she was "dismayed to find out the 911 call had been leaked to the media." The person who released it, she said, "lacked the integrity and the fortitude to honor" the gag order.

Prosecutor Jason Hermus and defense attorney Robert Rogers said that they had not leaked the audio and that the people they asked also said they had not.

Hermus said Dallas police are still investigating whether any of the department's officers released the call. Kemp asked Hermus to notify her if the police inquiry leads anywhere.

Judge Tammy Kemp presides over the 204th Judicial District Court as fired Dallas police officer Amber Guyger makes a court appearance at the Frank Crowley Courts Building in Dallas on Thursday. (Ryan Michalesko / Staff Photographer)

Kemp and the attorneys decided that jury selection will begin Sept. 6 — exactly one year after Jean's death. Potential jurors will first fill out a questionnaire, and those who are not disqualified will return Sept. 13 to be questioned by the attorneys.

There probably will also be two pretrial hearings in July, but those dates have not been set.

Testimony is scheduled to begin Sept. 23.

The Texas Rangers initially arrested Guyger on a manslaughter charge. But the Dallas County district attorney's office sought a murder indictment against Guyger because she intended to shoot Jean. In Texas, manslaughter is a reckless act.

Dallas police Chief U. Reneé Hall fired Guyger on Sept. 24 — the same day Jean was buried in a cemetery by the sea in St. Lucia, the Caribbean island where he grew up.

A lawsuit that Jean's family filed against the city and Guyger is pending in federal court. It is unlikely the civil case will go forward until the criminal case is resolved.