Sometimes, the absence of certain types data (for example, about someone's browsing habits) can be the data.

That in part is how they found Bin Laden

https://www.npr.org/2011/05/02/135930226/how-the-spies-found-bin-laden

MARTIN: The big break came last August when they linked into a compound in Abbottabad, Pakistan, north of Islamabad. The courier lived with his brother and their families in a massive house several times larger than anything in the surrounding area with incredible security, 18-foot walls and two security gates.

The house itself became the next big clue. It's in a relatively well-off community. The compound is valued around a million dollars. But the house had no internet access. And instead of taking the trash out, like the rest of their neighbors, the residents burned everything.