"It was a fully-intact .40-caliber bullet," Police Chief Michael Foligno said.
The Gantner Avenue School youngster "brought it to school and was showing the other kids in the playground," the chief said. "Luckily, one of the kids was smart enough to tell a teacher."
The school immediately went into a shelter-in-place and a K-9 from the Bergen County Sheriff's Office was summoned "to err on the side of caution and make sure there wasn't any danger," Foligno said.
The boy was removed from school, normal activities resumed after a sweep and both the fourth-grader and his mom were interviewed, the chief said.
"We're working with the prosecutor's office and following all protocols in investigating the incident and preparing a [delinquency] complaint against the boy," he said.
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