DALLAS — A grand jury will convene Monday to hear evidence in the case against former Dallas police officer Amber Guyger, who shot and killed 26-year-old Botham Jean at his South Side Flats apartment in early September.

Guyger was arrested on a manslaughter charge on Sept. 9, three days after the shooting. And after more than two weeks of protests calling for her termination, Guyger was fired from the Dallas Police Department on Sept. 24.

It's still unclear exactly what happened the night Guyger shot Jean, who lived in the apartment a floor above the 26-year-old accountant.

MORE: Reports on the shooting of Botham Jean

Guyger told authorities she mistook Jean's apartment for her own after she parked on the wrong garage level at their complex and worked a more than 13-hour shift. Once at the unit, she said she thought Jean was an intruder and fired her weapon.

Sunday, Jean's mother, Allison Jean, talked with WFAA about her struggles to find answers.

”You see, the one person who cannot speak is Botham,” she said. “He’s the one that I would have depended on for the answers.”

This is a developing story and we will be continuously updating throughout. Check back for new information and don't forget to download our free WFAA app to stay up-to-date on all news stories in the Dallas-Fort Worth area.