A body was found in the middle of a residential street in Saginaw on Monday night.
Residents said children found the body of a young girl, perhaps 3 or 4 years old, in a wrapped-up tarp near Round Rock Drive and Cindy Lane.
The child's legs or feet were tied together, residents said.
Saginaw police confirmed that the body of a person was found in the tarp but have not said how old the victim is.
Police said their investigation is just beginning.
The FBI was also at the scene on Monday night.
Police are looking for a red pickup truck with a splash of green paint on the passenger-side rear quarter panel.
NBC 5's Scott Gordon contributed to this report.