Former cop Kim Potter cried on the witness stand as she spoke about the "chaotic" moment she fatally shot 20-year-old Daunte Wright earlier this year in April, BBC News reports.
The 49-year-old ex-Minnesota officer maintains she unintentionally drew her firearm instead of her Taser when she killed the young driver.
Potter is now faced with two manslaughter charges over the shooting as her lawyers claim in her defense that the deceased had been resisting arrest.
According to Potter's tearful testimony, she noticed "a look of fear" on the face of another cop during the altercation.
"He [Mr Johnson] had a look of fear on his face. It's something I've never seen before," Potter said. "It just went chaotic."
"I remember yelling 'Taser, Taser, Taser', and nothing happened. Then he told me I shot him," she added as she wept.
On Thursday, the jury heard as ex-Brooklyn Center police chief Tim Gannon called Potter "a fine officer". Speaking on the witness stand, Gannon said that after taking a look at the footage taken following the incident, he saw "no violation" of "policy, procedure, and law". Closing arguments are set to start on Monday.
Wright died on April 11 after a run-in with cops in the suburbs of Minneapolis. He was stopped for a minor infraction while driving. Potter then discovered that a "gross misdemeanor warrant" for Wright's arrest had been issued.
Minutes later, shots rang out. In a panic, Potter had allegedly intended to use a taser but instead fired a handgun. The officer has since resigned from the force.
In bodycam footage of the incident, two police officers can be seen approaching Wright's vehicle, with Potter standing behind them. As one officer attempts to handcuff him, the 20-year-old manages to break free and jumps back into the driver's seat of the car to try and flee the scene.
During the struggle, Potter can be seen pulling out her firearm and shouting "Taser! Taser! Taser!" before firing a single gunshot.
The video, which is just over a minute long, was recorded on the bodycam worn by Potter.