[ceejayoz]

You asked "What did they do besides doxing him and confronting him online that helped?"

> The confession was online

The confession was made possible via their "antics", because he knew he'd been caught. Without the experience of being cornered and having to escape, he'd have likely ignored the message as a fishing expedition.

> they already had the vehicle ID

Getting that was part of their "antics", yes.

[Eisenstein]

You are right, I should have phrased the question better. What I meant by antics was the desire to confront him physically.