Amber Guyger

Former Dallas police Officer Amber Guyger, center, arrives for the first day of her murder trial in Dallas on Monday. Guyger is accused of shooting her black neighbor in his Dallas apartment. Tom Fox/The Dallas Morning News via AP, pool

DALLAS — A white Dallas police officer who fatally shot a black neighbor in his own home was distracted by a phone call with a colleague with whom she had been romantically involved, a prosecutor said Monday at the start of the officer’s trial.

Attorneys for Amber Guyger, 31, argued that she fired in self-defense based on the mistaken belief that she was in her own apartment and that Botham Jean was a burglar.

Jean, a 26-year-old accountant from the Caribbean nation of St. Lucia, “was doing no harm to anyone, which was his way,” Dallas County Assistant District Attorney Jason Hermus said in an opening statement.

Jean was in his living room eating a bowl of vanilla ice cream on Sept. 6, 2018, when Guyger entered the apartment, which was one floor directly above her apartment, Hermus said.

Hermus said Guyger had worked overtime that day, mostly involving office work that was not strenuous. He said jurors will see sexually explicit messages that Guyger exchanged that evening with a co-worker that discussed meeting up after her shift ended. He said some messages had been deleted from Guyger’s phone after the shooting.

During pretrial proceedings, prosecutors and defense attorneys sparred over whether those messages should be entered into evidence.

Botham Jean, Brandt Jean

Allison Jean, right, the mother of Botham Jean, and Botham’s brother Brandt Jean arrive for the murder trial of former Dallas police Officer Amber Guyger in Dallas on Monday. LM Otero/Associated Press

In his opening statement, defense attorney Robert Rogers dismissed the prosecution argument that there were unique signs that would have signaled to Guyger that she was on the wrong floor. In fact, he said, the identical look of the apartment complex from floor to floor often led to confusion among tenants, with dozens regularly parking on the wrong floor or attempting to enter the wrong apartment.

Rogers says the floors of the parking garage were not clearly marked so it was understandable when Guyger, tired from a long shift, pushed open a door and believed an intruder was inside.

Guyger “was on autopilot,” he said of her entrance to Jean’s apartment. “She had tunnel vision.”

Rogers also dismissed as “preposterous” the relevance to Jean’s death of Guyger’s sexual relationship with her partner.

The case is being heard by a jury that appeared to have a majority of women and people of color.

The shooting attracted intense national scrutiny for the strange circumstances and because it was one in a chain of shootings of unarmed black men by white police officers.

The trial’s outcome may hang on whether the jury believes that Guyger’s mistake was reasonable, according to legal experts.

Guyger was off duty but still in uniform when she shot Jean. She told investigators that after a 15-hour shift she parked on the fourth floor of the complex’s garage – rather than the third floor, where she lived – and found the apartment’s door ajar.

Three days after the shooting, Guyger was arrested for manslaughter. She was subsequently fired from the Dallas Police Department and charged by a grand jury.

The jury will have to decide whether Guyger committed murder, a lesser offense such as manslaughter or criminally negligent homicide, or no crime at all.

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