They are known as rovers: the United States Customs and Border Protection officers who patrol the baggage claim area at Kennedy International Airport, scrutinizing arriving passengers and looking for signs of illegal narcotics, food items or currency tucked away in pockets and luggage.

This week, for reasons that agency officials did not reveal, a rover pulled aside a man who had just arrived on a flight from Santiago, Dominican Republic. An examination of his luggage turned up something highly unusual: counterfeit New York State vehicle inspection stickers.

Customs officers found 935 of them hidden inside the man’s sneakers and a photo album, a haul that hinted at the possibility of an international counterfeit ring dealing in stickers.

“As far as I’ve seen — it’ll be six years in April that I’ve been at C.B.P. — this is the first time I’ve seen anything like this,” Anthony L. Bucci, a spokesman for the agency’s New York field office, said Thursday.