You man the search into his account by the San Fransisco PD? Who later cleared him of any wrongdoing? Note that Google, after hearing from the police, stood by their choice as well.
I strongly suspect we're talking past each other. The man under investigation didn't make "a search" that Google deemed unsavoury. The police department conducted a search of his account, looking for any additional examples of child pornography or abuse. You're confusing who actually performed the search (SFPD, not Mark), as well as what the search was for (searching through Mark's Google account photos, documents, and more, not Mark making a Google search).
I just want to know the context of that search that he made. It could very well be disqualifying, or it could be totally benign.