Published: Aug 19, 2013 5:01 PM EDT

LEHIGH ACRES, Fla.- A Lehigh Acres daycare owner, charged in the drowning death of a little boy, entered a not guilty plea today.

Melissa Smith is charged with aggravated manslaughter and three counts of child neglect.

Investigators say in June, Smith left 2-year-old Christian Byrd and three other children unattended in a portable pool. Christian drowned.