ARLINGTON (CBSDFW.COM) – It was named after an Arlington girl who was kidnapped and killed ten years ago, and now changes are coming to the Amber Alert, as a result of another local case.

The warning system uses media and electronic billboards to help police find missing children, who have been abducted, but in September, the Amber Alert will be used in other cases as well.

Governor Rick Perry signed a bill in June that will expand the alert to include adults who have mental disabilities.

“If they had already had that law in place, I really think things would have turned out differently,” said Deborah Hailey, who’s mentally disabled daughter, Tiffany Demus, disappeared last November. “A lot of people saw Tiffany; they just didn’t know she was missing.”

Tiffany, 31, had the mental capacity of a child. She wandered away from the family’s Mansfield home on November 23, 2010. After an extensive search, her body was discovered in an Arlington park.

“She was gone for about an hour, and I didn’t’ see her and that’s when I started to get concerned,” her mother said. “Five days later, they found her, face down in a creek.”

“We called the police and said ‘why is there not an Amber Alert?’ and they said ‘because she’s 31,’” said Michelle Mills who knew Tiffany well, “but mentally she was like a six- or eight-year-old.”

Mills owns Mary’s House in Arlington, a day facility for adults with disabilities. Tiffany was one of her first clients.

After Tiffany’s death, Mills petitioned lawmakers to change the criteria for the Amber Alert to also include adults with mental disabilities.

She originally wanted to create a new alert system named after Tiffany, but found it was easier to change the Amber Alert, which was already established and widely known.

Hailey now hopes the warning that wasn’t available for her daughter, will someday save others like Tiffany.

“I wouldn’t want to see another family go through what we went through,” she said, “Even though we had to go through this for it to take place, I’m glad that something came out of Tiffany’s death, something positive.”