Tweaked all the time, and that's a problem. so, there's some degree of playing catch up. >> sort of like a whack-a-mole, where you whack one and then something else pops up? >> it's not a bad analogy. >> reporter: in tara's case, detectives had identified four local people, three high school students and a dealer, who were involved in the drug sales that lead to her death. and after months of digging, they finally found the main supplier, 19-year-old alexander claussen. he was caught with more than 300 doses of 25i. >> alex, you have a right to remain silent. anything you say can and will be u...