The parents of a two-year-old found the girl dead outside their Dekalb County home, Monday afternoon. Police say the girl was killed.

Investigators believe the toddler was being watched by a 13-year-old sibling. When the parents returned home to their condo on Waldrop Trail, the girl was gone.

"That child's body was found outside of the condo," says police spokeswoman Mekka Parish.

On the way to the hospital, the parents flagged down a fire rescue unit, which took the toddler the rest of the way. The child was later pronounced dead.

Police believe they know what caused the girl's death, but they are not releasing that information at this time.

There is no clear motive in the two-year-old's death. Police have not made any arrests. They are investigating the death as a homicide.