Former Dallas police officer Amber Guyger is asking an appeals court to throw out her murder conviction for the 2018 shooting of Botham Jean—claiming the killing was self-defense, even though she shot Jean after she mistakenly entered his apartment. In a brief filed with Texas’s Fifth Court of Appeals on Tuesday—about a year and a half after Guyger was convicted and sentenced to 10 years behind bars—her attorney, Michael Mowla, argued that she had “acted reasonably” during the September 2018 incident.

Guyger, then a member of the Dallas police department, fatally shot Jean, a Black 26-year-old accountant, while he was sitting in his apartment eating ice cream. Guyger, who is white, said she had mistaken his apartment for her own at the Dallas apartment complex where they lived on separate floors. The jury that convicted Guyger dismissed her claims of self-defense, but now her attorney says that since she truly believed she was in her own home, she could not have had “evil intent” when she killed a man she thought was an intruder. “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,” Mowla wrote.