The gun that was used was owned by the mother, according to police.
WPXI learned that Hoffman's 10-year-old brother may have gotten the gun from their mother's purse while they were home alone.
"I don't think he's at the age where you can charge him with homicide. That's why I wanted my prosecutors to file a dependency petition to make sure he's being cared for properly," Zappala said.
Zappala said the boy was dealing with issues that required medication, but he added that the evidence suggests he was never getting that medication. Instead, his mother was selling it, according to Zappala.
"There's some issues of him being on medication, but not getting his medication; possibly the medication is on the streets. It's pretty bad stuff," Zappala said.
The 10-year-old boy has been removed from the home.