"While we were there at the residence, Sus1 and Sus3 arrived home," the police report said. "Sus3 made a comment that the Vic was locked down stairs because in December they had let him upstairs and he ate almost an entire bowl of fruit at one time."
The teenager was taken to a hospital for treatment and then placed in the custody of the Clay County Children's Division. A 2-year-old grandson living in the house was also taken away and placed in protective custody.
The neighbor, Crystal Anderson, who called the child abuse hotline told ABC News' Kansas City affiliate KMBC that she had seen the teen handcuffed to a door after going to the house to see his brother last month. Anderson said the boy's brother told her that he is "mentally challenged."
"He told me one time that they had to keep him chained up because he would eat raw meat out of the trash and that he would attack his mom all the time," Anderson said.
But Anderson said she did not feel right about what she saw and decided to make the phone call.
"They said he's mentally challenged... [but] you can call somebody and get [help]. You don't have to chain them to a pole in a basement. There's other options," she said. "I just feel bad for the kid."
At a protective custody hearing, a petition was filed alleging child abuse and neglect, according to Clay County juvenile court officer Alan Gremli.
The teen was present and so was his father.
"[The teen] is thin and showed me that he's probably put a little meat on a couple ribs since Monday," Gremli told ABCNews.com. "He was in a pretty decent mood. He wasn't angry, no animosity."
A judge decided that the teen would remain with his foster family at least until a March 7 hearing.
"[The teen] was aware of what was going on," Gremli said. "He told me he had been watching the news and doing okay at the foster home. They got to make homemade pizza the night before, which he hadn't done and thought was kind of cool."
The Kansas City Police Department did not immediately respond to request for comment from ABC News, but told the Associated Press that they are still investigating and have not yet turned over their findings to prosecutors for potential charges to be filed.