Dallas police officer Amber Guyger was fired after shooting down his neighbor Botham Jean

Dallas police officer Amber Guyger was fired on Monday, officials said, weeks after racist shots in which the off-duty white policeman killed his black neighbor, Botham Jean.

An investigation revealed that Guyger "engaged in prejudicial behavior when she was arrested for manslaughter," said Dallas Police Chief Renee Hall in a statement.

Guyger was arrested for manslaughter after shooting Jean earlier this month. The Fox News arrest affidavit said Botham ignored Guyger's "verbal commands" before opening fire.

Guyger recently ended a 15-hour team when she returned in uniform in the South Side Flats apartment complex. She parked on the fourth floor, instead of the third, where she lived, according to a sworn statement about the arrest warrant for the officer, suggesting perhaps that she was confused or disoriented at the time of the shooting.

She said that she had entered the apartment – which she thought was hers – after realizing that the door was unlocked and slightly ajar and that she had then seen a silhouette in the darkness. Guyger reportedly gave verbal orders because she believed that her apartment was burgled, then fired her gun and fired twice, the affidavit said.

When she turned on the lights, she realized that she was in the wrong unit, according to the document, which appeared to rest almost entirely on the officer's account.

Jean's family is challenging Guyger's version. John's family's lawyers also asked why it took three days for Guyger to be charged and why Guyger was so quick to use lethal force in his meeting with Jean.

Lee Merritt, a lawyer for Jean's family, also criticized the shooting investigation, saying the authorities were looking for evidence to discredit Jean.

Police executed several search warrants at Botham Jean's apartment following the murder, and investigators said they found several items, including a small amount of marijuana, FOX4 News reported.

Merritt said the research "highlights the harmful nature of [the police] investigation."

"They went with the intention of seeking some kind of criminal justification for the victim," Merritt said, according to USA Today. "It's a model we've seen before … we have a cop who has clearly done something wrong. And instead of investigating the homicide – instead of going to his apartment and see what they can find, instead of gathering evidence relevant to the investigation on the homicide – they went looking for ways to tarnish the image of this young man.

Fox News' Katherine Lam and Associated Press contributed to this report.