7-year-old finds gun and kills little sister; mom arrested A 7-year-old boy has accidentally shot his younger sister to death after finding an unsecured shotgun at their home in suburban Denver

WESTMINSTER, Colo. -- A 7-year-old boy accidentally shot his younger sister to death on Tuesday after finding an unsecured shotgun at their home in suburban Denver. Their mother has been arrested.

Police in the city of Westminster say the boy was playing with his 3-year-old sister when he found the loaded gun. Their 24-year-old mother, Michaela Dawn Harman, was home and was arrested on suspicion of child abuse resulting in death — criminal negligence. She was taken to jail.

It's not yet clear if she has an attorney who can speak on her behalf.

The boy and another of his younger siblings are in the temporary care of child welfare officials.

No other information was released.