A former Dallas police officer was charged with murder on Friday for shooting an unarmed Black neighbor whose apartment she said she mistakenly entered instead of her own, prosecutors said.

Amber Guyger, 30, surrendered to authorities after a grand jury indicted her on a charge of murder in the Sept. 6 death of Botham Jean, 26, Dallas County District Attorney’s spokeswoman Kimberlee Leach said by phone.

Guyger, who lived in an apartment one floor below Jean’s unit, told investigators she mistook Jean for an intruder after she entered his apartment by mistake and he appeared in the darkness, police said.

Guyger walked into the apartment after returning from a work shift and was able to enter because Jean’s door was slightly ajar, according to a Texas law enforcement account of the incident.

The killing of an unarmed black man by a white officer in uniform sparked demonstrations in the Texas city, with protesters calling for Guyger, a four-year veteran of the Dallas police force, to be charged with murder.

The shooting followed several years of scrutiny of law enforcement in the United States over questions of racial bias.