NORTH LAUDERDALE (CBSMiami) — It’s every pool-owning grandparent’s darkest nightmare: a grandchild falling into the pool and drowning.

That nightmare was reality for the grandparents of a three-year-old boy visiting their home Saturday afternoon.

According to BSO’s Dani Moschella, around 2 p.m. the boy and his parents—mom is six months pregnant—were taking a nap on a bed at the grandparents’ home.

The three-year-old asked his parents whether he could go see his uncle, who was lying on a bed in another room. The parents said OK.

Instead of going to that room the boy went outside, via a partially-cracked sliding door, into the pool area.

The boy then approached the pool and fell in.

A short time later, the uncle went outside and saw the boy’s sandals floating in the pool. Because the water was dark and murky, he said he couldn’t see the boy.

He immediately entered the pool and pulled the boy out, then administered CPR. The boy was rushed to the hospital but was already dead.

The boy’s parents were too distraught to talk to CBS4.

A large crowd, including members of the family’s church, gathered outside the grandparents’ house Saturday evening.

The Broward Sheriff’s Office is treating the boy’s death as an accident.