NEWTON, N.J. — New Jersey investigators were looking into a routine complaint from a woman who said her ex-boyfriend was harassing her, when they uncovered something far more dire: The 25-year-old man had stockpiled weapons and far-right propaganda and had talked about shooting up a hospital.

Two months later, New Jersey State Police responding to a crash in the same county discovered illegal assault weapons in the back seat of a car. Later, they found 17 more firearms, a grenade launcher and neo-Nazi paraphernalia in the driver’s home.

The arrests of the two men rocked law enforcement officials in Sussex County, raising fears that far-right extremism is growing in this sleepy, rural area in New Jersey .

It is impossible to know if the two arrests so close together are a fluke or signal of a growing white supremacist movement in the county, law enforcement officials said. The two men appear to have no connection to one another.