The trail runs off of the American Tobacco Trail and goes to N.C. Highway 55.
A passerby spotted the body around 6:30 a.m. Wednesday and called 911.
Investigators said they would like to speak with anyone who saw Williams on Tuesday or early Wednesday morning.
Anyone with information is asked to call Investigator A. Cristaldi at (919) 560-4440, ext. 29322 or CrimeStoppers at (919) 683-1200. CrimeStoppers pays cash rewards for information leading to arrests in felony cases and callers never have to identify themselves.