He was found cold and alive on Thursday in a jumble of vine and thorns.
But the 3-year-old has published a remarkable detail about these forest days: A bear has accompanied him.
"He made a comment about having a friend in the woods – his friend was a bear," Maj. David McFadyen with the Sheriff's Office of Craven County told CNN Monday. "In the emergency room, he started talking about what was happening in the forest, and he said he had a friend who had a bear with him while he was in the forest."
McFadyen said there are bears in the forests of Craven County. However, there is no evidence to prove that Casey was one. All that matters, McFadyen said, is that there was something to comfort him during the three days.
"We are very pleased that he had this kind of comfort, there were very brutal conditions there, the first night dropped to 20 degrees, the second night we had 2 inches of rain," he said.
The three-year-old boy will undergo a forensic psychological examination this week, McFadyen said, but for the time being, the authorities are giving Casey time to recover and settle in with his family.
"He has not been interviewed yet, what happened is he's a three year old boy," said McFadyen. "Until we do the forensic exam, we do not have a final idea."
His family searched him for 45 minutes before calling 911, Craven County Sheriff Chip Hughes said.
"He was When we walk through the forest, we can not find him," his great-grandmother told the 911 dispatcher. "The others come through the house, but he left him there and he went somewhere and we can not find him."
Search and rescue teams from across the state came together immediately to defy the deceptive terrain and expected low temperatures Casey.
The FBI, NCIS, dozens of volunteers, and the US Marine Corps also joined the search for the boy, Hughes said.
The authorities employed helicopters, drones and K-9 units, Craven County Emergency Management Director said Stanley Kite. WTVD reported that divers also assessed nearby ponds.
Casey, who weighs 25 pounds and is 2 feet 4 inches tall, according to the authorities, was in conditions so bad that volunteers were turned away from search.
Hughes said his team was worried about the "extreme cold" as temperatures dropped to near freezing, but despite all adversities, they found him.
"It was people who gave us tips and hints," Hughes said. "We met everyone immediately and it paid off."
On the third day, a tip led the search team to a place where they heard the three-year-old boy calling for his mother, Hughes said. He was found 40 to 50 meters away.
CNN's Madeline Holcombe contributed to this report.