Former Dallas police officer Amber Guyger is escorted by a security detail as she arrives for her murder trial at the Frank Crowley Courthouse in downtown Dallas, Tuesday, Sept. 24, 2019. Guyger is on trial for shooting and killing her unarmed neighbor Botham Jean in the Dallas apartment building they both lived in. (AP Photo/LM Otero)

DALLAS (AP) — A white Dallas police officer who fatally shot her black neighbor in his apartment last year had no drugs or alcohol in her system at the time, a police detective testified Tuesday.

Detective Eddie Ibarra's testimony during the second day of Amber Guyger's murder trial marked the first time her toxicology results have been publicly revealed.

Guyger was off duty but in uniform when she shot Botham Jean last September. Guyger has said she mistook his apartment for her own.

Prosecutors have said Guyger should have noticed she was on the wrong floor, and contend she was distracted by a phone and text conversation with a colleague with whom she had a sexual relationship. Guyger's attorneys have argued that she fired in self-defense based on the mistaken belief that she was in her home and that Jean was a burglar.

Jurors heard her frantic call to 911 following the shooting. In the call, Guyger says "I thought it was my apartment" nearly 20 times. She also says: "I'm gonna lose my job" and "I am going to need a supervisor." The recording of the 911 call was previously obtained by a Dallas TV station.

Prosecutors said Monday that 26-year-old Jean, an accountant who grew up in the Caribbean nation of St. Lucia, was sitting in his living room, eating a bowl of vanilla ice cream, when Guyger, 31, walked into his home and shot him.

Jurors on Tuesday watched body camera footage from Officer Michael Lee, who was among the responders to the shooting. Guyger, who was later fired from the force, looks panicked when she appears briefly in Lee's footage. In it, Guyger says, "I thought it was my apartment. I thought it was my apartment," as Lee moves past her and puts on a pair of gloves.

Lee testified that despite officers' efforts, Jean didn't open his eyes or otherwise communicate with first responders.

Senior Cpl. Dale Richardson testified that he was told during the investigation that Guyger's set of keys were found dangling from Jean's door. He said that when tested, Guyger's key made a light on the lock blink red and it would not operate, while Jean's key made the lock blink green and make a whirring sound that indicated it was operating.

Guyger's defense has said she was able to enter the apartment because the door wasn't locked.

Dallas police officer Michael Lee, right, listens and watches his body cam footage played for the jury during the trial of former Dallas police officer Amber Guyger Tuesday, Sept. 24, 2019, in Dallas. Guyger is accused of shooting her unarmed black neighbor in his Dallas apartment.  (Tom Fox/The Dallas Morning News via AP, Pool)
Underneath a body camera image of former Dallas police officer Amber Guyger outside Botham Jean's apartment, Dallas police Sgt. Breanna Valentine responds to questions from Assistant District Attorney Jason Hermus during the trial of Guyger Tuesday, Sept. 24, 2019, in Dallas. Guyger is accused of shooting her unarmed black neighbor in his Dallas apartment.  (Tom Fox/The Dallas Morning News via AP, Pool)
A photo of victim Botham Jean leans against Judge Tammy Kemp's bench during the murder trial of former Dallas police officer Amber Guyger, Tuesday, Sept. 24, 2019, in Dallas. Guyger is accused of shooting Jean, her unarmed black neighbor, in his Dallas apartment.  (Tom Fox/The Dallas Morning News via AP, Pool)
Dallas police officer Amber Guyger, left, is pictured on police body camera footage in Botham Jean's apartment as Dallas Police arrive, in video that was played for the jury in Guyger's murder trial, Tuesday, Sept. 24, 2019, in Dallas. Guyger is accused of shooting her black neighbor in his Dallas apartment.  (Tom Fox/The Dallas Morning News via AP, Pool)
Former Dallas police officer Amber Guyger leaves the courtroom during a break in morning proceedings in her murder trial, Tuesday, Sept. 24, 2019, in Dallas. Guyger is accused of shooting her unarmed black neighbor in his Dallas apartment.  (Tom Fox/The Dallas Morning News via AP, Pool)
Former Dallas police Officer Amber Guyger arrives for her murder trial at the Frank Crowley Courthouse in downtown Dallas, Tuesday, Sept. 24, 2019. Guyger is on trial for shooting and killing her unarmed neighbor Botham Jean in the Dallas apartment building they both lived in. (AP Photo/LM Otero)
Allison Jean, center, the mother of Botham Jean arrives with family members for the murder trial of former Dallas police officer Amber Guyger in Dallas, Tuesday, Sept. 24, 2019. Guyger is on trial for shooting and killing Botham Jean, her unarmed neighbor, in the Dallas apartment building they both lived in. (AP Photo/LM Otero)
Brandt Jean, center, the brother of Botham Jean arrives with family members for the murder trial of former Dallas police officer Amber Guyger in Dallas, Tuesday, Sept. 24, 2019. Guyger is on trial for shooting and killing Botham Jean, her unarmed neighbor, in the Dallas apartment building they both lived in.  (AP Photo/LM Otero)