This week, the testimony of Amber Guyger's police patrol partner has activists calling for a new investigation into a 12-year-old shooting case.
On the stand, Officer Martin Rivera testified about an on and off again sexual relationship with Guyger and text messages he deleted from the night she shot Botham Jean.
Prosecutors said Guyger was distracted when she shot Jean. The defense argued Rivera's relationship with Guyger was not relevant.
Wednesday, Antoinette Washington joined activists with Mothers Against Police Brutality to call for a new investigation into an officer-involved shooting from 2007.
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"It blew my mind to see him in another case," said Washington. "I knew he was no good then and justice is fixing to prevail because he killed my child for no reason."
According to NBC 5 news reports in 2007, Rivera was responding to a call about a candy bar theft and disturbance at a Pleasant Grove 7-Eleven.
Rivera told police he shot 20-year-old Brandon Washington, believing Washington was reaching for a weapon when he put his hand in his pants pocket.
A Grand Jury heard the case and declined to charge Rivera.
Rivera's testimony this week did not touch on the 2007 case, but Collette Flanagan with Mothers Against Police Brutality said Rivera demonstrated a lack of integrity when he deleted text messages with Guyger.
"It's really as plain as the nose on your face: if you would destroy evidence for your lover, you certainly would destroy it for yourself in my opinion," Flanagan said.
The group is calling on Dallas police to fire Rivera and the Dallas County DA's Office to investigate Washington's 2007 shooting death.
"Look at the case again, re-visit what actually happened, what did he say happened, who were the witnesses, who were the people who were talked to?" said Sara Mokuria with MAPB. "Give it a second look with fresh eyes."
The Dallas County District Attorney's Office said it can not comment on anything having to do with the Guyger case.
The Dallas Police Department, in an email to NBC 5, wrote: "Per Judge Tammy Kemp of the Dallas County 204th Judicial District Court, there will be no statements or comments made by the Dallas Police Department during the course of the Amber Guyger trial. Facts and evidence related to this case are a matter of public record and please refer to court proceedings for these details. We urge each of you to let the criminal justice system take its course."