HOUSTON -

A 4-year-old girl drowned during a pool party in northwest Harris County.

On Monday at 6:30 p.m., the girl was discovered face-down in the pool at the Northchase Village apartment complex on Sylvanfield Road.

Residents said the girl was visiting some family members who live at the complex and that they were having a pool party. 

It's unclear who was supervising.  Harris County Sheriff's deputies said there were a lot of children in the water. 

"That's when they noticed her -- when everybody got out of the pool," said one resident. "So, she was probably under for a minute."

Paramedics performed CPR on the girl for almost an hour before she was rushed to the hospital, where she died.