Maddox’s parents were notified immediately of the discovery by law enforcement. Formal identification of the body will be done by the medical examiner’s office, Gastonia Police said.
FBI Supervisor Jason Kaplan said it was too early in the investigation to know whether foul play factored into Maddox's disappearance.
"The investigation is not over," Kaplan said. "In law enforcement, we will not take anything for granted... a lot of people have lost sleep."
Kaplan added there were still many unanswered questions, and the public's help was needed to gather more information.
"We still want to hear from the others," Kaplan said. "Please call the tip line (704-869-1075)."
On Wednesday, Ian Ritch, the Maddox' father, took questions from reporters at the Greater Gaston Baptist Association in Gastonia. Ian said Maddox took off running in the opposite direction of him and his friend Saturday at Rankin Lake Park.
"He usually runs but will stop to give me a chance to pick him up," Ian said.
Ian said his son's disappearance left him sleepless for several days, and he hasn't eaten.
"I feel guilty for letting him get so far ahead of me," Ian said.
Investigators say they're still looking for witnesses as they wait for the autopsy results. Authorities hope they get a hold of joggers who were at the park Saturday, as well as a man who Chief Helton said may have been among the last to see Maddox Ritch.
"In a white pick-up truck," Chief Helton said. "I think it was a crew cab truck, had running boards loading a silver kayak out of the water. He had a camouflage hat on... So he was coming out of the water right around this time. We need to talk with him."