Two brothers were arrested Thursday after police officers found bomb-making instructions, an arsenal of assault rifles, and Nazi paraphernalia in their Mount Sinai, Long Island home, The New York Times reported.

According to the Times, Edward Perkowski, 29, was arrested on weapons and drug charges after police found marijuana and psilocybin mushrooms during the search. His brother Sean, 25, who also lives in the home, was arrested on an outstanding bench warrant.

Police reportedly entered the residence on a search warrant early Thursday morning and discovered a disturbing trove of materials. These items included $42,000 in cash, six assault rifles, a handgun, a shotgun, four rifles, a stun gun, and a black binder filled with instructions on how to build a bomb.

The binder also contained a racist manifesto, CBS reported. The rifles rested near photos of Adolf Hitler, flags with swastika insignias and books about white power.

“Today’s search warrant might have prevented a deadly, violent incident, like the one we recently saw in Orlando,” Suffolk County police commissioner Timothy D. Sini said at a news conference in Yaphank, according to the Times. “We neutralized a clear public threat.”