It happened about 15 minutes after midnight Thursday on Webster Avenue in Claremont.
Nearby, police and EMTs had responded to an 18-year-old who had been shot in the stomach.
But, that's when gunfire erupted again.
Police say a bullet was fired and went through a parked ambulance and shattering the front windshield.
The two EMTs inside were not injured.
Investigators say it's unclear what led to the shooting or who pulled the trigger.
The scene remains secured as detectives work to piece together what happened.
The 18-year-old victim of the nearby shooting is listed in stable condition Thursday morning at a local hospital.
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