CLAYMONT, Del. (WPVI) -- Authorities are investigating two separate swimming tragedies in New Castle County, Delaware.
A 4-year-old drowned in his backyard swimming pool and a teenager is fighting for his life after going under the water at an apartment pool.
One of the incidents happened at a home on Franklin Avenue in Claymont.
Witnesses say there were at least forty adults and children enjoying a holiday cookout.
There were multiple children in the pool and adults were socializing when, around 7:30 p.m. Wednesday, chaos erupted. A 4-year-old boy named Dominic had gone missing.
Witnesses say they checked the pool and saw nothing.
The neighborhood was scoured. When police arrived they checked the pool again, but there were no signs of Dominic.
Then a second wave of police officers arrived, and that's when the tragic discovery was made.
"One of the children thought they felt something," a witness said. "That's what made the cop start coming out of his gun and his belt. And as he was getting ready to dive in, a family member jumped in before he did, and found the little fella."
Next door neighbor and cookout attendee Jacob Lasse was part of that frantic search that ended in horror.
"We probably had about thirty, forty people looking for this young man," Losse said. "They checked the pool a couple times."
A few hours earlier a lifeguard pulled a 15-year-old boy out of the pool at the Georgetown Manor Apartments near New Castle.
CPR was administered and the teen remains in critical condition at an area hospital.
State health officials say the 4-year-old boy's death marks the first July 4th drowning in Delaware since at least 2016.
Lucinda Kettner, a YMCA aquatic expert, says adults and lifeguards must be ever vigilant at poolside - no matter how large the crowd.
"You've got to scan not only the top of the water but below the surface as well," Kettner said. "Drowning doesn't look like someone flailing their arms around. It can be a very silent thing, they just slip under water - and it's quick. It can be under ten seconds."
Both of the cases in New Castle County are under investigation by county police.
Send a News Tip to Action News
Learn More About 6abc Apps
2 swimming tragedies in Delaware under investigation