This guy has 1031 rep.
1 answer of score 0.
Member for 3 days.
The user's Reputation tab gives us some clues. 100 rep for association bonus, and then as @Journeyman Geek has suggested, reputation which was obtained from a deleted question, which hasn't been removed via the SQL maintenance tasks.
We can use the Wayback Machine to see what the question was, and how the reputation was allocated. Here's a snapshot of the answer from the 7th of February, 2016.