WESTMINSTER, Colo. (AP) — A 7-year-old boy who accidentally shot and killed his 3-year-old sister used his mother’s loaded shotgun that he found on the couch in the home’s family room, according to police.

According to the arrest affidavit for the mother, Michaela Dawn Harman, 3-year-old Ruby Jackson was shot in the chest as she played “swords” with her older brother Tuesday morning. Ruby was using a broomstick, but at some point her brother picked up the .12 gauge shotgun before accidentally firing at his sister, the document said.

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Michaela Dawn Harman (credit: Westminster Police Department)

Harman was outside smoking a cigarette at the time, but when she heard the single shot she immediately realized she had left the gun leaning next to the couch before falling asleep the night before, the affidavit said. She said she had recently loaded it because she was afraid there were people breaking into her home.

According to the affidavit, Harman had reported hearing men’s voices in her basement and garage over the previous three days. Police had been called to the home each time but did not find any evidence of forced entry, the document said.

When police responded to the shooting, an officer asked anyone else inside the home to announce themselves so they could account for everyone. According to the affidavit, the boy appeared at the top of the stairs with his hands up and said “I’m sorry, I was playing with the gun. I didn’t know it was loaded.”

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The boy and a 2-year-old sibling were put in the temporary care of child welfare officials.

Harman was arrested on suspicion of child abuse resulting in death. She appeared in court Wednesday and was advised of the possible charge she could face. A judge allowed her to be released with a promise to return for her next court hearing, according to court records.

A telephone message left for the supervisor of the public defender’s office, which represented Harman at the hearing, was not returned.

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