The missing something is the wife, I think. She called the cops. So you have NJ looking to protect the wife from the allegedly crazy husband, using "gotcha" state gun laws and her stated fears. It's an extreme example of the common policy that any domestic problem can lead to serious impairment of gun "privileges" in many states.
But what was exigent that gave them lawful and full access to his vehicle with no warrant?
No, his own mother called the cops. His wife was back in Colorado, I imagine.