Even if you didn't shed it everywhere, we really just need a database of a subset of people, which we can use to match close relations to and drastically narrow

Even if you didn't shed it everywhere, we really just need a database of a subset of people, which we can use to match close relations to and drastically narrow down the search. e.g. how the Golden State killer was finally found, https://en.wikipedia.org/wiki/Joseph_James_DeAngelo#Arrest_and_trial https://en.wikipedia.org/wiki/Joseph_James_DeAngelo#Arrest_a... Your DNA is fundamentally public information.