MADISON, Wis. -

A man who found a severely malnourished 15-year-old girl walking barefoot outside in pajamas said she was bleeding from a gash on her nose and crying.

Mike Vega said Wednesday that the teen he found walking near her Madison home Feb. 6 also had scrapes and a big bruise on her forehead and was so scrawny he mistook her for an 8-year-old.

Vega said he saw the girl as he was driving on Siggelkow Road, near Valley Drive on Madison's southeast side.

"She had came up to the car, and I rolled the window down and I said, 'Do you need help?' And she said, 'Yes,' and reached out for my hand in the car door," Vega said.

Vega said while they waited in his car for an ambulance to arrive, she told him her stepmother had thrown her down the basement stairs and that she escaped through a window.

Seeing her without any socks and shoes prompted Vega to wonder how many steps she endured to get to get to where he found her.

"I mean, I don't know where I found her in relation to the house," Vega said. "But she was purple on her feet and she was getting frostbite."

Police said the girl told officers her father and stepmother had kept her confined to the basement for years and had starved her and even forced her to eat her feces.

The teen told police that she was forced to live in the unfinished basement of her family's house on Treichel Street since about 2006.

A doctor who specializes in child abuse examined the teen Friday and diagnosed her condition as "serial child torture with prolonged exposure to definite starvation," according to a police incident report.

Charges are still pending against the girl's father, Chad G. Chritton, and stepmother, Melinda J. Drabek-Chritton. They were arrested on Friday on suspicion of child abuse and neglect.

A Dane County judge on Tuesday set the couple's bail at $20,000 each. The judge told prosecutors that the suspects could be released if a criminal complaint is not filed by Thursday. The two younger stepchildren in the home are now also in protective custody.

Vega said he is thankful the girl is being cared for in a different environment.

"You could see right through this girl's eyes that she had no love," Vega said. "And the night that it happened, I told my wife that we should pray for her because no one in her house is."

A probable cause affidavit said the girl weighs 70 pounds and experienced prolonged starvation. But a close family friend said a medical condition is to blame.

"Chad and Melinda are just sweethearts," said family friend Sam Stenbroten.

Stenbroten said the Chrittons did everything they could to manage their daughter's serious dietary challenges.

"They always gave her three substantial meals of food, and she didn't enjoy eating those," Stenbroten said. "She would rather eat things that she would find. They believed that she had a medical condition that made her want to eat other things besides food."

Stenbroten said the girl said she preferred defecating in containers rather than using the restroom. He said the girl's family believed she had a medical syndrome.

"I heard it was pica, but I'm not sure what that is," Stenbroten said.

WISC-TV tried to confirm if the girl has pica and, if so, when it developed. Neither police nor the Dane County District Attorney's Office would confirm, citing the open investigation and protection under the HIPPA law.

Dr. Sumona Saha, of the University of Wisconsin Hospital's Gastroenterology Division, explained that those with pica will crave nonfood items.

"Pica is a really an unusual or unnatural appetite for substances that really aren't food," Saha said.

Those with pica will eat things like dirt, chalk and paper, the doctor said. It can affect pregnant women, children and those with Crohn's disease. It can also affect those who aren't getting enough iron, Saha said.

WISC-TV tried to confirm if the girl has pica and, if so, when it developed. Neither police nor the Dane County District Attorney's Office would confirm, citing the open investigation and protection under the HIPPA law.