As the PI raised the camera and looked through the light-adjusted lens, though, he couldn't be more surprised by what he saw. Because, the two people in bed were Richard McMillan and ... a little girl! The PI watched as the middle-aged man thrust and heaved into the young girl of ... what? Nine? Ten years old?
The PI had seen some sick things in his life, but the sexual abuse that Richard was doing to this girl ... it made him violently ill. But he pushed onward and took the pictures anyway.
He retreated back into the bushes, thinking about the ramifications of what he just saw and had evidence of. This sort of thing wouldn't just end a marriage. It could destroy the entire McMillan company.