NASHVILLE, Tenn. (WKRN) — A 12-year-old boy was transported to a Nashville hospital in critical condition after being found unresponsive in a Madison pool Tuesday night.

The Nashville Fire Department responded around 7:30 p.m. to a reported drowning at an apartment complex on Berkley Drive, off Gallatin Pike South in the area of East Due West Avenue.

When paramedics arrived, the department said they found an unresponsive child surrounded by bystanders, as a security guard performed CPR on the boy.

Metro police said the 12-year-old boy was playing with three friends in the complex’s pool, where there was no adult supervision.

The other children noticed the boy was on the bottom of the pool’s deep end and pulled him out, according to investigators.

Police said the boy was transported to Vanderbilt Children’s Hospital, where he remained in critical condition Wednesday morning.

An investigation is being conducted by the Metro Nashville Police Department’s Youth Services Division.