Malnourished teen Indiana - A 58-year-old Indiana man is set to appear in court on Friday to answer to child neglect charges after he confessed to locking up his allegedly mentally ill teenage granddaughter earlier in the week.

Steve Sells, who lives at 3400 block, Forrest Terrace, says he locked up the "strong" 15-year-old to protect himself from her. He claims she had attempted to attack him with a knife once.

However, Anderson Police say the malnourished teen in Indiana, who weighed less than 40 pounds when she was taken to the St. Vincent Regional Hospital on Monday, may not survive. The condition of the teenager was so critical that medics had her airlifted to the Peyton Manning Children's Hospital in Indianapolis.

Detective Joel Sandefur described the unidentified teenager as looking like a skeleton. He said her condition is uncertain. "I don't think people understand. She was starved," he said. "We wouldn't accept treatment of an animal this way, let alone a human being, let alone someone that's 15 years of age."

Sells had reportedly taken the malnourished teen in Indiana for a medical checkup on Monday. He told medics that she suffers from a "chromosome problem in her brain" and had fallen from the stairs. He later confessed to locking the malnourished teen up after medics insisted that his story did not completely explain the state of her physical condition.

It is unclear how long the malnourished teen in Indiana had been locked up in her room. Sells gained custody of the teen after she was abandoned by her mother- his daughter-in 2009. Reports indicate that she was withdrawn from school in October 2010 and had her last medical examination in January 2012.

In Court documents, police say the room, in which the malnourished teen in Indiana was padlocked in, was poorly heated and covered in feces. There was also blood on the floor. Officers reportedly found a mattress, a space heater, a bucket, blankets and a bowl of oatmeal in the prison cum room.

Sells' wife Joetta, has also been charged with child neglect and abuse in the malnourished teen Indiana case. According to USA Today, the Department of Child Services had initiated legal action against the Sells in 2011. It is unclear why it was stopped. Meanwhile, a 4-year-old child, who was also living with the Sells, has been taken into the custody of Child Services.