Members of Philando Castile's family believe he was purposefully targeted by officers in Minnesota because he was black.
Last year, the President's Task Force on 21st Century Policing recommended police departments collect and analyze demographic data on all stops, searches and seizures.
Choi also said on Friday that the decision about whether to use a grand jury during the case, as is tradition, or decide himself if charges should be brought forth in the officer-involved shooting death of Philando Castile in Falcon Heights, Minnesota.
Castile's girlfriend, Diamond Reynolds, a passenger in the auto, said the two officers who stopped them said the vehicle had a broken tail light.
Reynolds's real-time broadcast was powerfully affecting - her composure as Castile bled, slowly dying, beside her; the agitated police officer with his gun still pointed; her appeals for help to those watching live; her four-year-old daughter's attempt to comfort her later as she wept handcuffed in a cruiser.
The department's 2015 annual report notes he gave Cub Scouts a tour of the station and volunteered with St. Paul's Cinco De Mayo celebration. Andy Mannix and Brandon Stahl write: "Late Thursday, state officials identified the officer who fatally shot Philando Castile during a traffic stop as Jeronimo Yanez".
Several videos, including squad vehicle video of the incident, have been collected, but St. Anthony officers don't wear body cameras, the agency said.
Reynolds said her daughter has remained strong through everything, describing her as her "warrior".
The previous year's report includes a photo of Yanez solemnly standing guard at a memorial to fallen officers at the state Capitol.
Minnesota's governor says a suburban police officer probably wouldn't have shot a black motorist dead if the driver had been white.
Yanez's attorney hasn't returned several messages from The Associated Press.
According to TIME magazine, Castile was a noble character in his community, serving kids as a cafeteria supervisor at J.J. Hill Montessori Magnet School in Saint Paul, Minnesota.
"The default perspective has always been from the authorities, from the police, but now we're seeing it from the other side, and a counter-narrative emerges", Hermida says. "We must speak up until we are heard and real, effective changes are made", she concluded.
"This has to cease". Some Minnesota demonstrators stood together to watch the news footage, and roughly a dozen St Paul police officers gathered in a nearby church carpark, an apparent increase in force from earlier in the evening. The group swelled to over 1,000 for a time as people marched from the school vigil. Dayton waded through the crowd as protesters chanted: "What do we want?" "They're symptomatic of a broader set of racial disparities that exist in our criminal justice system", he said after arriving in Poland for a North Atlantic Treaty Organisation summit.
Speaking later, he said America was "horrified" over the Dallas shootings and there was no possible justification for the attacks.
Potter reported from Minneapolis.