An expert witness and Brooklyn Center's former police chief testified Thursday that ex- officer Kimberly Potter had the legal authority to use a Taser or gun on Daunte Wright when he attempted to flee a traffic stop earlier this year.

The two testified on the first day that Potter's attorneys called witnesses in her case, which will likely conclude Friday with testimony from Potter and a psychologist who will testify about "slip and capture errors" that cause a dominant behavior to inadvertently replace a less-dominant one. Potter's defense has argued that she meant to use her Taser when she fatally shot Wright once in the chest with her handgun on April 11.

Prosecutors attempted to raise doubts about the defense witnesses' bias and credibility by noting their personal ties with Potter, their allegiance to law enforcement and their limited assessment of her character.

Former Brooklyn Center Police Chief Tim Gannon, who resigned from his post under pressure days after the shooting, testified that he reviewed Potter's body camera footage and footage from a squad camera.

"When I viewed both camera angles and had the data in front of me, I saw no violation," Gannon said.

"No violation of what?" asked defense attorney Earl Gray.

"Of policy, procedure or law," Gannon said.

Under cross-examination by Assistant Minnesota Attorney General Matthew Frank, Gannon acknowledged that he and Potter were friends and that he spent "personal time with her family." He testified that he felt bad for her after the shooting and still does.

However, under redirect from Gray, Gannon said that did not influence his testimony.

"Ex-Police Chief Gannon, would you lie under oath to help a friend out?" Gray asked.

"Sir there's a reason I'm an ex-chief — no one gets me to do something or say something I don't believe in," Gannon said. "I wouldn't lie."

Gannon previously testified that he felt pressured by the city's "elected body" to choose between resigning or being fired because he refused to immediately fire Potter instead of following a much longer internal investigatory process, and because of how he handled protests that erupted after the shooting.

Frank attacked the defense's argument that Wright could have injured two other officers at the scene had he put his car in reverse. Potter's defense has argued that scenario and a second hypothetical — Wright's car fatally dragging one officer as it sped forward — were grounds for using a Taser or deadly force, such as a gun.

Police stopped Wright for expired tags and a dangling air freshener and attempted to arrest him when they discovered an arrest warrant for carrying a gun without a permit. Wright, 20, broke free of an officer, Anthony Luckey, attempting to handcuff him and jumped back in his car, which sped forward into another vehicle after Potter shot him. Sgt. Mychal Johnson was standing outside the front passenger door at the time and reaching into the vehicle. Two squad cars were parked behind Wright's car.

"You had some people flee from you at a traffic stop?" Frank asked.

"Yes I have," Gannon said.

"Did any of them drive in reverse to the squad car when they fled from you?" Frank asked.

"No they have not," Gannon said.

"Doesn't make any sense for somebody to put it in reverse when there are two squads behind them to flee?" Frank asked.

"No," Gannon said.

Frank also pushed Gannon on his testimony that Johnson was "hanging inside the car." Under questioning, Gannon agreed with Frank that Johnson was "leaning into" the car.

"It's true, isn't it, that in making that arrest officers still have to use reasonable force?" Frank asked in response to Gannon's prior testimony that Wright's warrant mandated that police arrest him.

"Correct," Gannon said.

"You're not saying that anytime somebody tries to get away in their vehicle and drive off during an arrest an officer can shoot them?" Frank asked.

"That is correct," Gannon said.

The defense began its case by calling Stephen Ijames, a police officer from Springfield, Mo., in his 44th year in the profession. Ijames testified that Potter had the legal authority to use her Taser or gun on Wright, noting that the officers who encountered him would have been in an elevated state of vigilance after learning about the warrant.

It would have been a "dereliction of duty" for the officers to allow Wright to leave, Ijames said.

"The very nature of flight and resistance brings with it danger to people in the path," he testified.

Defense attorney Paul Engh tried to undermine a prosecution witness' assertions that even deploying a Taser would have been unreasonable because of the risk it posed to others at the scene. A young woman was in the front passenger seat of Wright's car.

"Police officers have to deal with the circumstances presented to them," Ijames testified. "It's a balance between the need to use that tool... with the risk of what would happen if you hit the wrong person. We shoot close all the time."

Frank meticulously cross-examined Ijames on his several overseas trips to represent various law enforcement organizations in an attempt to show his bias toward officers.

Ijames had told Engh that he was currently reviewing evidence in three other criminal cases involving police officers, and that his opinions in those cases did not favor the officers. But Frank pressed him, getting him to acknowledge that he is reviewing a fifth case that is "more supportive of the officer." The unspecified case is also in Minnesota.

"I do have another one I just thought of that I've not done anything on as far as a formal report or anything," said Ijames, who later admitted under further questioning by Frank that he had authored a report in the case.

Frank and Ijames argued in circles after the prosecutor asked if shooting someone in a vehicle could cause "collateral injury" because of the potential for the vehicle to move.

"It would depend completely, sir, on the circumstance — if we're on a downtown street compared to in the middle of a cornfield," Ijames said.

Colleen Fricke, who worked with Potter as a Brooklyn Center officer and now works in Brooklyn Park, testified that Potter was a good officer and her friend. Fricke, on the verge of tears, testified that she was assigned to take Potter from the shooting scene back to a meeting room at police headquarters.

"I saw her curled up in a corner of the room," Fricke said in a quivering voice.

The defense also called three character witnesses who testified about Potter's reputation for peacefulness and lawfulness — Thomas Hall, a Champlin resident who is friends with her children; retired Brooklyn Center police Sgt. Frank Roth, who supervised her; and Brooklyn Center officer Samuel Smith II, who worked with her.

"She's always been an extremely peaceful person and no matter what was going on or happening, she was always there to help people," Hall said.

Jurors will likely receive the case next Monday after hearing closing arguments from the defense and prosecution. Potter, 49, is charged in Hennepin County District Court with one count each of first- and second-degree manslaughter.