Two Florida women were arrested after investigators said they left five children home alone -- and a 4-year-old girl tossed a knife that cut a 9-year-old boy in the back of the head.

The boy’s injury took place this past Friday in Port St. Lucie when his younger sister threw the knife toward a television, police said. The knife bounced off the stand and struck him in the head.

Doctors treated his cut at a hospital, police said. They later released the boy and police said he was in "good health."

Mugshots for 30-year-old Julie Belliard, left, and her mother, Marie Pierre, 55. (Port St. Lucie Police Department)

The boy’s 8-year-old brother summoned help from a neighbor, Kristen Pusateri, WPBF-TV reported.

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“I mean, he was just bleeding everywhere from the head,” she told the station. “So, it was scary.”

Police accused the children’s grandmother Marie Pierre, 55, of leaving them home alone. The nine-year-old was the oldest. The youngest was three, police said.

The children’s mother Julie Belliard, 30, was at work and Pierre had gone to pick her up, according to police.

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Pierre and Belliard were arrested on child-neglect charges. Belliard was aware the children had been left home alone, police said.

Police who responded to the home noticed the children appeared to be unwashed and unkempt with several bug bites on their legs, WPTV reported.

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In a news release, police said the two women were “aware the home they live in with the children is in deplorable conditions and the conditions are unfit for human living.”

Child welfare workers took custody of the children, police said. It wasn't clear if the women had attorneys.