The Dallas Police Department on Monday fired an officer who fatally shot her neighbor inside his apartment this month, an episode that gripped the city and led to protests over the killing of an unarmed black man in his own home at the hands of law enforcement.

The department’s chief, U. Reneé Hall, announced the termination of the officer, Amber R. Guyger, citing her arrest in the killing of Botham Shem Jean, who lived above Ms. Guyger in a Dallas apartment complex. Ms. Guyger, who was off duty, entered Mr. Jean’s apartment the evening of Sept. 6 and fired her service weapon twice, striking him once in the torso.

Ms. Guyger, 30, was placed on administrative leave immediately after the shooting and charged with manslaughter several days later. Chief Hall faced mounting pressure to fire Ms. Guyger, but she said at a town hall-style meeting last week that state and federal laws prevented her from doing so, without citing specifics. She also argued that taking action could harm the investigation into the death of Mr. Jean, 26.