Dartmouth police on Wednesday showed the weapons found inside the home where man held officers at bay for several hours.
Police said Kevin Pacheco sent threatening emails Tuesday to Roger Williams University Law School. The university alerted Dartmouth police, who found Pacheco barricaded inside his family's home.
Pacheco remained holed up for eight hours until police cut power to the house and Pacheco surrendered peacefully.
Dartmouth police said they found two pistols and four rifles inside the Pacheco home. They also found a cache of ammunition.
Police also said they recovered books about becoming a serial killer and making methamphetamine.
Investigators said they did have some indication of what they were dealing with because Pacheco's parents notified them about the weapons inside the house.
Pacheco, 36, was being evaluated at St. Luke's Hospital in New Bedford. He faces charges of extortion and making threats.