WATCH: Former Dallas Cop Amber Guyger Says ‘I Wish He Was the One With the Gun and Had Killed Me’ and Apologizes for ‘Mistakenly’ Killing Black Neighbor Botham Jean as She Gives Tearful Testimony at Her Murder Trial

White former Dallas police officer Amber Guyger broke down in court as she began testifying in her own defense on Friday on charges that she murdered her unarmed neighbor in his apartment after she entered by accident.