The Coast Guard pulled the two 12-year-old girls from the water in Belmar on Thursday evening.
It happened near Ocean Avenue and 9th Avenue around 7 p.m.
"We had a tough night in Belmar tonight," said Matt Doherty, Mayor of Belmar.
They searched into the night in the water and on the beach in Belmar. Two children were pulled from the water and the news could not be worse.
"One is deceased and the other is on life-support now at Jersey Shore Medical Center, they are cousins, both of them are Belmar residents, and both of them attend Belmar Elementary School," Doherty said.
There were no lifeguards on duty Thursday, they don't start until Saturday, and the two girls had no adults with them.
"Police officers themselves went into the water and was able to take one of them out. Belmar First Aid responded, worked on CPR all the way to the hospital," Mayor Doherty said.
The other child was found later in the evening, it is the nightmare of every parent raising children near the water.
"We say this continuously about not swimming unless there are lifeguards present, but it can be very tempting unfortunately," Mayor Doherty said.
Two police officers pulled the lifeless children from the water.
"It's a lot when they take a child out that's lifeless and face down, so they're heroic in their actions but it takes an emotional toll on them," Mayor Doherty said.
There had been reports of a possible missing third swimmer that turned out to be unfounded.