Former Dallas police officer Amber Guyger has been indicted on a murder charge in the killing of her neighbor in his own apartment. (Kaufman County Sheriff's Office/AP)

Former Dallas police officer Amber Guyger has been indicted on a murder charge in the killing of Botham Jean, a neighbor whom she fatally shot after entering his apartment in September, according to authorities.

The indictment was announced by Dallas County District Attorney Faith Johnson. Guyger had been arrested in the days after the shooting and charged with manslaughter. Johnson said a grand jury had returned with the murder charge.

According to the Texas code, a person has committed murder if he or she intentionally or knowingly caused the death of another person or intended to injure someone while committing a dangerous act. A conviction on a first-degree felony can bring a maximum sentence of 99 years.

Jean’s death drew international headlines as another instance of an unarmed black man killed by a police officer. And the details of the case raised questions about Guyger’s conduct.

Police said Guyger was still in uniform after a shift when she went into Jean’s apartment, thinking it was hers. Guyger has said she confused Jean for an intruder and shot him when he refused her commands, according to court documents.

But Jean’s family has said they believe she knocked on Jean’s door before shooting him. Guyger was fired by the department in late September after Jean’s death sparked weeks of protest.