I admit that I don't know squat about DNA, but the fact that she remembered his face weighs heavily on the way that I feel. If all other tests can be said to be tampered with, according to SA's claim that he was framed, then one DNA test could be too.
When I was 18, I worked in a small, retail store. One evening, just as the sun went down and it started to get dark, a man came in, pulled a gun with a silencer on it, and told me to open the cash register. At first I thought he was joking, but as soon as I realized he was not kidding, I looked at him and decided that I would memorize his face. After I gave him all the money, he told me to lay on the floor and not get up for 10 minutes or he would kill me. After what was probably 20 minutes, I crawled to the back of the store and called the police and the owner. After the police came, I was sent home, quite shaken. About a month later, I was called down to identify the man in a photo lineup. I immediately was able to pick him out of the other photos. Then, there was a lineup where I had to go behind glass to identify him. It was as if he had a spotlight on him and I again picked him correctly and immediately. It was only later that I found out that over a month's time, he had robbed 4 businesses and had killed two people. I can tell you that this is a big reason why I feel that if PB identified SA, it is most likely he was the one who raped her. It might not seem logical to people who believe that DNA can't be messed with. But, these are some of the same people who insist that other tests were tampered with.