So someone was paid to find those images??? Sounds like a disturbing job.
And even if the % of child porn was low(.0003% of 3.7 billion), it still amounts to over 11,000 images. Who would want a job to check those out - ugh!!
That's a big risk, but people in those positions are put through some pretty tough psych evaluations, and their private lives are subject to much more scrutiny than Joe Blow.
The "investigators" I'd be worried about are the ones who aren't acting on behalf of any agency. Private citizens who "stumble across child porn" and report it are probably surfing on some legaly questionable sites.