"They worked on him in the ER for 20 minutes before pronouncing him" at Hackensack University Medical Center, a responder said.
Responding police officers conducted CPR and got a pulse after the boy was pulled from the pool around 6:30 p.m. Thursday, they said.
It wasn't immediately clear how long he'd been in the water.
EMS workers took over and continued CPR after AirMed One touched down at nearby Stone Point Park around 7 p.m.
The chopper reached HUMC's main campus in Hackensack around 7:15 p.m.
Paramedics brought the parents there by ambulance.
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