Jean was home alone when Guyger, still in uniform after her shift, entered the apartment, Dallas Police Chief Ulysha Renee Hall said Thursday.
Guyger parked her vehicle on the fourth floor, entered the building and walked toward what she thought was her apartment, according to an arrest warrant affidavit.
The door was slightly ajar as she tried to use her key, which has an electronic chip, to enter. When she was able to open the door, she saw the interior was nearly completely dark, according to the affidavit. She described seeing a large silhouette and, believing there was a burglar in her apartment, drew her firearm.
Her verbal commands to Jean were ignored, the affidavit said, and Guyger fired two shots at Jean, striking him once in the torso.
Guyger then entered the apartment, called 911 and started administering first aid to Jean.
She turned on the lights while on the phone with 911, and when they asked for her address, she realized she was in the wrong apartment.