Bergen County Prosecutor Gurbir Grewal said he was temporarily withholding identities until next of kin could be notified.
Borough police were called to the West Clinton Avenue home at 10:18 a.m. after the boy ran to a neighbor and told them "his parents weren't breathing," Grewal told Daily Voice.
The body of his 36-year-old mother was found upstairs, while his 44-year-old father's was found in a basement utility room -- the victim of a self-inflicted gunshot wound, the prosecutor said.
"We are investigating this incident as a domestic violence based murder-suicide," Grewal told Daily Voice, moments after concluding a news conference at the scene.
The Bergen County Medical Examiner was headed into the West Clinton Avenue home just after 5 p.m.
State child welfare authorities were taking care of the boy, who has three other siblings from the same parents.
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