COPS searching for missing a six-year-old boy who went missing from a North Carolina park this have found a body.

Investigators believe they have discovered the remains of Maddox Ritch near the Old Dallas Highway in Gastonia, five days after he vanished from a park.

In a statement the FBI said: "Maddox’s parents have been notified of the discovery. The investigation is ongoing."

His dad Ritch had spoken of his guilt at losing his autistic son, who does not talk, and feared Maddox may have been abducted.

He said: "I feel guilt for letting him get so far ahead of me... As soon as I got to the point where I couldn’t see him anymore, I started panicking."

Maddox was last seen on Saturday wearing an orange shirt with the words, "I am the man", near a lake at a North Carolina beauty spot.

His dad Ian and a friend lost sight of the lad when he was running alongside Rankin Lake Park's reservoir, which provides Gastonia's drinking water.

Ian told People: "These past few days have been hell for me. I’m so broken.

"People are making it out like I did something to him. I would never hurt my little boy. I love him to death and I just want him back.

"I’ve been feeling the blame since this happened. I just wish I would have caught him before he got too far away from me. It’s broken my heart to think that I just let him get too far away.”

FBI agents have joined two dozen agencies and more than 100 volunteers to comb dumpsters, land and waterways in and around the park.

Special agent Jason Kaplan told the ABC the FBI was exploring all possibilities, including abduction.

He said: "We're also going to make sure we search every inch of land around here to make sure he's not simply lost."

City of Gastonia spokeswoman Rachel Bagley said the family had been walking around the lake when "they lost sight of him, and no one has seen him since".

Search and rescue and emergency teams had "re-searched the lake and surrounding areas as well as reviewing video from surveillance cameras at the park and nearby homes and businesses".

Members of the Charlotte Fire Department have used boats to check the lake, while about 120 volunteers have been searching more than 1,400 acres around the lake.

All activities at the park have been cancelled and the site has been closed to visitors, as dogs from the National Centre for Missing and Exploited Children comb the area.

Ian says he was walking with Maddox when he started running behind a jogger.

The dad said he allowed his son to go ahead for fun but when he sped up Ian wasn’t able to catch up and he lost sight of Maddox.

He said Maddox’s mum Carrie was “hysterical” when she found out her son was missing.

She posted on Facebook: "My main focus is bringing him home. Thank you all for your love and support.

"I am completely heart broken. I need him home. I want him in my arms.

"I want to see his smile and hear his precious laughter. I know God is with him protecting him.”