Investigators say they uncovered a large cache of suspected homemade explosives, firearms, and explosive-making materials at a Denville home following a months-long investigation.
Denville, NJ – A Denville man has been arrested after a months-long investigation led authorities to what prosecutors described as a destructive device manufacturing operation, resulting in the seizure of more than 100 suspected homemade explosive devices.
Joseph Rizos, 37, of Denville, was charged following the execution of search warrants June 24 at his residence on Avondale Road, according to the Morris County Prosecutor’s Office, Denville Police Department, and Morris County Sheriff’s Office.
Investigators said Rizos was detained during a motor vehicle stop before officers executed the search warrants.
More than 100 suspected explosive devices seized
Authorities said investigators discovered a home laboratory containing explosive precursors commonly used to manufacture homemade explosives. Also recovered were blasting caps, cell phones, firearms, and ammunition.
A subsequent search of a shed on the property led to the seizure of approximately 109 individual containers of suspected homemade explosive material that prosecutors said were capable of causing “massive destruction.”
Officials also said investigators did not locate a permit required by the New Jersey Department of Labor and Workforce Development’s Division of Public Safety and Occupational Safety and Health to store the explosive materials.
As a precaution, nearby homes were temporarily evacuated while bomb technicians and hazardous materials specialists secured the scene.
Investigation began in March
The Morris County Prosecutor’s Office said the investigation began in March and alleges Rizos operated a destructive device manufacturing operation during 2025 and 2026.
Rizos has been charged with one count of second-degree recklessly risking widespread injury or damage and four counts of third-degree possession of destructive devices. He remains held at the Morris County Jail pending a motion for pretrial detention under New Jersey’s Criminal Justice Reform Act.
Prosecutor Robert J. Carroll praised the investigators and assisting agencies involved in the operation.
“I want to recognize the hard work and persistence of our investigators in shutting down this potentially dangerous operation,” Carroll said. “I also wish to thank our local, state, and federal partners in providing timely assistance with this volatile situation.”
Carroll added that authorities are aware the arrest may prompt speculation due to other events occurring in northern New Jersey but said investigators cannot discuss additional details, including the defendant’s alleged intent, while the investigation remains active.
“Given the ongoing nature of the investigation, law enforcement cannot discuss additional details at this time, such as the defendant’s intent. More will be reported to the public at the appropriate time.”
The investigation remains ongoing, and prosecutors said additional charges may be filed.