Authorities believe an 8-year-old family member let off a round after finding the handgun inside an apartment.
The child's mother brought the victim to the hospital with a gunshot to the tricep just before 3 a.m. Friday.
Police were seen examining a vehicle parked outside the hospital.
Officers also responded to a Jersey City home to search for a weapon.
----------
* Get Eyewitness News Delivered
* More New Jersey news
* Send us a news tip
* Download the abc7NY app for breaking news alerts
* Follow us on YouTube