Amber Guyger, the white former Texas police officer who killed her unarmed Black neighbor,  Botham Jean, in his own home lost an appeal Thursday to overturn her murder conviction.

A panel of three Texas state judges ruled that a Dallas County jury had sufficient evidence to convict Guyger of murder in the 2018 shooting of the 26-year-old accountant, CBS reports. 

The judges upheld her 10-year sentence, writing: "That she was mistaken as to Jean's status as a resident in his own apartment or a burglar in hers does not change her mental state from intentional or knowing to criminally negligent.  We decline to rely on Guyger's misperception of the circumstances leading to her mistaken beliefs as a basis to reform the jury's verdict in light of the direct evidence of her intent to kill."

According to CBS, Guyger appealed the conviction in April, arguing that she killed Jean by misake and that her conviction should not have been for murder, but criminally negligent homicide. The sentence for criminally negligent homicide is six months or up to 2 years in state jail.

In September of 2018, Guyger entered Jean’s apartment in Dallas, Texas and shot him to death while he was eating ice cream on his couch. During her trial, she testified that she thought she had entered her own apartment in the complex where they both lived, and therefore “had the right to act in deadly force.”

In new appeal, Guyger’s attorneys argued that the evidence originally submitted in the case "was legally insufficient to prove beyond reasonable doubt that Guyger committed murder."

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They claim Guyger was confused about where she was in her apartment complex since both the third and fourth floors where her and Jean’s apartments were located look identical.

"Her mistaken belief negated the culpability for murder because although she intentionally and knowingly caused Jean's death, she had the right to act in deadly force in self-defense since her belief that deadly force was immediately necessary was reasonable under the circumstances," the appeal read.

Guyger had both a taser and pepper spray on her along with the gun she used to kill Jean. Her lawyers argued that officers are not trained to use non-lethal weapons “when faced with a deadly situation.”

"Despite the tragic consequences, considering all the evidence — whether admissible or inadmissible ... Guyger acted reasonably," the appeal read, claiming Guyger "simply missed" the clues she was entering the wrong apartment.

During the trial, Guyger’s attorneys claimed that Jean’s death happened due to the “malfunction” on his door and the “absurd design” and “incompetent management” of the apartment building.

Guyger has been in prison since October of 2019.

Guyger’s defense attorneys could still ask the Texas Court of Criminal Appeals, the state's highest forum for criminal cases, to review the appeals court's ruling.