The agents initially removed the cobras and delivered the turtles to Mr Franco's house.
They then obtained a search warrant to investigate his property and also discovered a tank containing a live baby Morelet's crocodile and tanks containing alligator snapping turtles, a common snapping turtle, and five diamond back terrapins - all of which are protected species.
Mr Franco also admitted during questioning to having received 20 king cobras in two prior shipments - but he said all of those snakes had died in transit.
If convicted on smuggling charges, he could face up to 20 years in prison.
King cobras are the world's longest venomous snakes, and, when provoked, can be highly aggressive.
Click for more trending news