According to police reports, the 12-year-old girl was walking alone near the park, when a man emerged from a nearby alley and exposed himself. Reports said the girl then ran to a neighbor's house, and the man disappeared.
The girl's mother, Jackie Dalrymple, said she wants neighbors in the area to be aware of the crime.
"I'm definitely worried that it will happen to someone else," she said. "I'm real worried he is actually going to get somebody, one of these little kids here at this park."
Reports describe the man as a tall, skinny white male with a beard. He was wearing all dark clothing.
Anyone with information should contact Dayton police at 333-COPS.