Jefferson had been babysitting her 8-year-old nephew at her mother’s home on Oct. 12, 2019, when a neighbor called a non-emergency police line to report that a door was ajar.
While playing video games, Jefferson and her nephew heard a noise in the backyard and she grabbed a handgun from her purse before walking toward a window.
Dean, who had responded to the call and was in the family's backyard, ordered her to put her hands up before firing into the window, fatally striking Jefferson.
Police have said that Dean opened fire after “perceiving a threat.”
Dean was later charged with murder and he resigned from the police department.
The trial comes more than two years after Jefferson was killed.
Today is long overdue. It has now been 708 days since Atatiana Jefferson was murdered and we have waited every day to see Aaron Dean stand trial," said Fort Worth District 8 City Councilman Chris Nettles. "I believe that the activism of our community, and our persistence for demanding justice, helped bring this day to fruition."
Jefferson's sister filed a lawsuit last Wednesday in federal district court saying, Zion Carr, Jefferson's nephew, “suffered extreme and severe mental and emotional distress, anxiety, terror and agony” from watching his aunt die while officers performed CPR.
A separate lawsuit was filed by Jefferson's sister in May seeking $10 million in damages for wrongful death. The defendants named in that suit included Dean, the city of Fort Worth, former Chief of Police Ed Kraus and former Mayor Betsy Price.
A gag order was issued last year preventing prosecutors and defense attorneys from speaking publicly about the case.