I have never heard of such a law in the United States before, but I have heard of such in some African countries.
It is highlighted on page 1 of the ADF&G regulations
http://www.adfg.alaska.gov/static/regulations/wildliferegulations/pdfs/bear.pdf
From your link
“......In Units 1-5, and in Unit 8, bears wounded by a hunter count as the bag limit for the regulatory year. “Wounded” means there is a sign of blood or other sign that the bear has been hit by a hunting projectile............”
It would seem that rule only applies in areas 1, 2, 3, 4, 5 and 8. So it would seem he must have been in one of those areas.
Near as I can figure there is at least 25 Units.
So that rule is only in place for less than 25% of the hunting units.
Not defending him - just saying...........