DALLAS (AP) — Last September, a white police officer shot and killed an unarmed black man in his own apartment. That much is settled.

But nearly every other aspect Amber Guyger’s murder trial for the killing of Botham Jean remains cloaked in controversy as opening statements in the case are set to start today.

For some, the shooting was a tragic accident with circumstances that can only be described as “very unique.” Others place it in pattern of white officers killing black men that, they say, points to systemic problems in American policing.

A jury will ultimately have to reach consensus on whether Guyger committed murder, a lesser offense or no crime at all. On the eve of trial, one of the only points of agreement about her case in Dallas is that it has the potential to profoundly affect the relationship between police and residents.

Dr. Brian Williams, the former head of the city’s police oversight board, called the trial a “flashpoint” that could significantly bolster or deeply damage public confidence in the police.

“This is an opportunity for Dallas to show that there is a way of handling these complicated and controversial issues of police use of force against minority citizens in a way that is fair and transparent and assures accountability for law enforcement,” Williams said.

Guyger, 31, was off duty but still in uniform when she shot Jean. She told investigators that after a 15-hour shift she confused Jean’s apartment with her own, which was directly below his, and mistook the 26-year-old accountant from the Caribbean island nation of St. Lucia for a burglar.

Guyger said she parked on the fourth floor of her apartment complex’s garage — rather than the third floor, where she lived — and found the apartment’s door ajar, according to an affidavit.

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 with murder.