[michael1999]

Parallel construction is also used to launder electronic surveillance sources, so wiretap is just as likely. Although running machine vision on every picture in google maps does sound like something the sigint people would do.

[kjaftaedi]

Agreed, but with the target unwilling to contact even his family in 10 years, and being in a completely different country than the one looking for him .. these things make the wiretap theory a little watery as well.

Your second theory would only work assuming google is participating in blanket facial recognition with various law enforcement.. which while possible, would be a small scandal if revealed.