Could be!!! My heart goes out to this family. My daughter is autistic too. She use to love to run away from you and get you to chase her, but, she would keep running. She use to freak me out. I had to get a babysitter one evening, a person who had sat with my daughter before and specialized in special needs kids. She broke a window in her bedroom and threw some toys out the window. When the sitter opened the front door to go round and get the toys, my daughter took off. Of course the sitter chased her, my daughter was just to fast. When I got home they hadn’t been able to find her for over half hour. I had to call police. My daughter was 5 or 6 at the time and couldn’t even cross a street safely, she didn’t know how. And there was a very busy street about 2 blocks away. I thought for sure I would never see her again. Thankfully an older couple found her and called police. She was missing about 2 hours all together. Some of the worst 2 hours of my life.
I bet that was hell to go through. Another unusual aspect of this case is that Nadia likes science and had mentioned taking her camera and trying to get pictures near the wooded area but they mentioned early on that she absolutely hated to get dirty.