A private eye says he was running on pure instinct when he helped apprehend a teen accused of stabbing a shop worker over Pokémon cards in a hobby store in Auckland's Newmarket.
A Hamilton 16-year-old will appear in Youth Court.
Thomas James says such incidents and lower level crimes are fairly common in the area.
He says it was a dangerous situation.
"He made a decision when he left the house that morning, or wherever he left, to carry a knife on him. You only carry a knife if you're prepared to use it."
LISTEN ABOVE

Duncan Greive: media commentator on Disney Plus expanding their ESPN offerings
02:52

James Smith: National Road Carriers Spokesperson on the Government's plan to loosen freight restrictions
02:49

Barry Soper: Newstalk ZB senior political correspondent on the attempted assassination of Donald Trump at the White House Correspondents' Dinner
05:29