NORTH LAUDERDALE, Fla. – Broward Sheriff's Office detectives are investigating how Branario Joseph, 5, and his 6-year-old brother, Jakye Joseph, ended up dead inside a pool with closed black metal gates in North Lauderdale's Silver Palms community.

While deputies know the family has a history with the child welfare system, the BSO's Child Protective Investigations Section took custody of their siblings, a 4-month-old baby and 1-year-old toddler, Thursday.

Two brothers, ages 5 and 6, drowned at this community swimming pool in North Lauderdale.

Their mother, Wildine Joseph, believes the boys snuck out and got through the fence. She told Local 10 News in tears that one of them was taking swimming lessons and was overly confident in the water.

"He thought he could swim, but he cannot swim," she said.

Drowning is the leading cause of death for children ages 4 and younger.

The boys were rushed to Northwest Medical Center in Margate, where they were pronounced dead late Wednesday night.

Detective Barbara Dyer is asking anyone with information about the boys' death to call 954-321-4262 or Broward Crime Stoppers at 954-493-8477.