Yusef Khela was playing with two other children near police headquarters on Civic Center Drive when they all fell in shortly before 5 p.m., township police said.
Two got out of the water, but the third became trapped.
Yusef's friends quickly summoned police, who created a human chain to try and rescue the boy, "but he slipped under the ice before they could reach him," the department said in a release.
Firefighters eventually got him out of the water and conducted CPR, police said.
Yusef was taken to Robert Wood Johnson University Hospital in New Brunswick, where he was pronounced dead nearly three hours later, they said.
Six police officers and two firefighters were treated for hypothermia, they said. Two of the officers and a firefighters were taken to the hospital.
Another officer was hospitalized after being involved in a crash en route to the scene, police said.
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