police checked files for known sexual offenders living near the crime scene. one stood out. kenneth ray johnson had just moved to texas city after serving 25 years for rape. >> he was really a good suspect because he was new to the area. he didn't want to cooperate at first, but then he did. he had several alibis, if i'm not mistaken. >> johnson denied any involvement. since he was on parole he was wearing an ankle bracelet that tracked his movement using gps technology. it showed johnson was at home at the time of the rape and his dna did not match the dna of the rapist. >> i never questioned that he would be found. i knew that you he was going to pay for what he did, one way or another. >> but would he be caught before he could strike again?