An off-duty Dallas police officer who fatally shot her neighbor in his apartment, claiming she mistook the unit for her own, told the authorities that the door was already ajar when she entered and that she shot him after he ignored verbal commands, according to court records released on Monday.

The officer, Amber R. Guyger, 30, who has been charged with manslaughter, could face additional charges in a case that has led to accusations that the officer received preferential treatment and debate about whether race may have played a role in the deadly encounter between a white police officer and a black man in his home.

On Monday, the Dallas County district attorney, Faith Johnson, insisted that the investigation into the death of the neighbor, Botham Shem Jean, 26, had not ended and that her office could seek charges “including anything from murder to manslaughter.”

“We’ll present a thorough case to the grand jury so that a right decision can be made,” Ms. Johnson said at a news conference.