The family believes traces of the substance were on the suspects feet because the footprints left behind killed the grass.
"For something to basically almost burn and kill the grass within that quick would have to be some sort of poisonous substance," Jeff Petka said.
The Petkas turned the video over to Cobb County police, who are now investigating. They hope the video will lead to an arrest.
"Luckily we caught it in time and I just want to stop whoever did this and make sure it doesn't happen to anybody else," Jeff Petka said.
The family said they now bring their child's toys inside at night.
Neighbors are sharing the information on social media and taking steps to stay vigilant.
"Our next door neighbors bought cameras, but they just haven't installed them, so they're going to install their cameras," Kathleen Petka said.
The Petkas said as far as they know, no one else in the neighborhood reported anything similar and they believe it was a random act.