The boy's 11-year-old sister survived after he apparently helped her reach the rocks along the riverbank.
Authorities were called to the scene around 6:20 p.m. Wednesday after receiving reports that three children had entered the river. According to Lora, the surviving girl said her younger brother's actions may have saved her life.
"The little boy had placed his hand on her head while he was trying to get himself up," Lora said. "In doing so, she ended up going underwater and she felt a rock, so she used the rocks to climb out. He created conditions for her to get out."
Emergency crews from multiple agencies across Bergen and Passaic counties responded Wednesday evening, deploying rescue boats, dive teams and drones in an extensive search.
The search continued through Wednesday and Thursday nights, with crews combing the riverbanks and nearby bridges. On Thursday and Friday, boats and divers returned to the water with additional support from the Passaic Valley Sewerage Commission.
Before the girl's body was recovered, Lora urged the community to rally around the grieving families.
"We're holding out with hope that she can be found, but right now, the family needs to know the support and the love of the community," he said.
Miggins said the girl's family remained near the Pulaski Park boat launch throughout the search and expressed gratitude for the tireless efforts of first responders.
"There was a large police presence with drones, helicopters, dive teams and even sonar equipment scanning the river," Miggins said. "They're doing everything they can. The mayor is doing everything possible to help recover her."