The shooting on early Saturday occurred inside a home in Fort Worth, Texas.
Police arrived at the house after a neighbor called the non-emergency police number, noticing Jefferson’s doors were open and the lights were on, the Fort Worth Star-Telegram reported, Presstv Reported.
Jefferson, who was playing video games with her nephew, heard a commotion and went to the window — where she was shot by a white police officer standing outside.
Body camera footage shows the officer entering the home using a flashlight and spotting someone inside standing near a window and telling her, "Put your hands up — show me your hands," before shooting seconds later. At no point does he identify himself as an officer.
The police officer, who was called by the neighbor to check on the Jefferson's residence opened fire on Jefferson, killing her without warning her properly.
Police said the evidence would be passed on to the district attorney "to determine the final outcome."
The officer in the shooting, who has been with the police department for about 18 months, was placed on administrative leave pending an investigator into the incident.
Lee Merritt, an attorney for Jefferson's family, said Jefferson had been babysitting her 8-year-old nephew at the time of the shooting.
Marquis Jefferson, the victim's father, described her death as senseless. "That's my one and only daughter. I'll never forget that."
Analysts believe racial profiling, particularly of black people, is consolidated in US society.
A recent study suggests that black people are 2.5 times more likely to be killed by police than white people and about 1 in every 1,000 black men can expect to be killed by police.
For black women, the rate is 1.4 times more likely than white women, according to the study.