DALLAS (CBSDFW.COM) — The murder trial for a fired Dallas police officer who shot an unarmed man in his own apartment last year has been delayed.

Attorneys for Amber Guyger argued that their involvement in a previously scheduled trial with another client, that could run into the month of August, would impair their ability to “adequately prepare” their defendant’s case.

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Guyger, 30, is charged with murder for the killing of 26-year-old Botham Jean last September in his downtown apartment.

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Guyger had worked several overtime hours as a Dallas police officer the night she went home from work, and walked into Jean’s apartment and shot him. Guyger told police it was nearly completely dark inside the unit at the South Side Flats apartments when she shot Jean twice. She said she’d mistook the apartment for her own and thought Jean was a burglar.

The Dallas County Medical Examiner’s Office determined Jean died from gunshot wounds to the chest and abdomen. His death was ruled a homicide and Guyger was fired from the Dallas Police Department.

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Judge Tammy Kemp granted the continuance, which now pushes Guyger’s jury trial from August 12 to September 23.