I'm not sure what this has to do with my comment. Is your point that they should not have bothered to investigate further because they found that there happened to be a TOR exit node? If so, I'm not sure it's a better situation, where the police say "eh, he's probably not trading in child porn himself. We can let this one go." That's just sloppy policing.
The point is not whether he was responsible for the child porn traffic, but whether they have an obligation to investigate, and I think they do. In this case, that means a raid, since it's an individual and not a business (a business would likely have people that would speak out, and individual mean that if he's guilty, there's no reason for him to incriminate himself). Even so, raids on businesses happen as well, when there is a belief a evidence might be destroyed.
The point is not whether he was responsible for the child porn traffic, but whether they have an obligation to investigate, and I think they do. In this case, that means a raid, since it's an individual and not a business (a business would likely have people that would speak out, and individual mean that if he's guilty, there's no reason for him to incriminate himself). Even so, raids on businesses happen as well, when there is a belief a evidence might be destroyed.