GLOUCESTER CITY — A New Jersey man is accused of setting off a homemade explosive device — and having what federal authorities called "substantial quantities of bomb-making materials" at his home.

Gloucester City police said officer were called shortly before 4 a.m. on Aug. 26 to Bellum Strength and Conditioning and found the entrance damaged by the blast.

Police said, after an investigation aided by Camden County prosecutors and the FBI, 35-year-old Dwayne Vandergrift Jr. was arrested two days later. Police said residences on his block were evacuated for a time until the home was deemed safe.

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The U.S. attorney's office said Vandergrift's home contained "numerous weapons, including an unregistered short barreled rifle, several tactical vests outfitted with body armor and loaded 30-round ammunition magazines, and a marijuana grow operation containing approximately 85 marijuana plants."

Investigators also found evidence on his computer that he'd recently researched how to construct and use explosive devices, including pipe bombs and pressure cooker bombs, the office said.

He was charged with malicious use of explosives, unlawful possession of two destructive devices, and a firearms charge. The malicious use of explosive charge carries a maximum prison term of 20 years and a maximum fine of $250,000. The charges for possession of the unregistered destructive devices and short-barreled rifle carry maximum prison terms of 10 years each and maximum fines of $250,000.

Authorities said security camera footage showed Vandergrift fleeing the area moments before the device exploded, badly damaging the front door and shattering glass at the gym.

Vandergrift remained in custody in the county jail; it's unclear whether he has an attorney and a listed number in his name was out of service Sunday.

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