They were looking for 46-year-old Gregory Gawrysiak.
Investigators say he's a member of an anti-government extremist group known as the Sovereign Citizens Movement. The police were looking for a stockpile of illegal firearms.
Two years ago they took away Gawrysiak's guns after he allegedly made threats to kill police officers.
Investigators say they found a handgun in his house on Emerald Avenue Thursday, and more weapons at a relative's house in Mantua: a rifle, another handgun, and a shotgun.
"He was not allowed to purchase guns. He had no permit in New Jersey to purchase or own guns. And he used a false address in Pennsylvania to purchase guns in Pennsylvania," said Camden County Prosecutor Warren Faulk.
The prosecutor says Gawrysiak was a threat to the community because of his affiliation with the Sovereign Citizens Movement.
Followers believe that federal and state governments lack legitimate authority and that the law doesn't apply to them.
But Gawrysiak's neighbors say they never felt threatened by him.
"He's always been nice to us and he's always been nice to anybody. If anybody in the neighborhood needed anything, he was the guy to go to. He's not a threat to anybody, he has a heart of gold," said Daniel Gray.
His neighbors say he had strong opinions about the government, but they never thought he could be capable of violence.
"He was more of like an educator, somebody who was trying to educate people about law, about their rights as a civilian, a human. Even with religion and stuff like that, he very much lived by the Bible," neighbor Blair Slavin told Action News.
Gawrysiak was held on $500,000 bail even though there's no evidence he was planning an assault of some kind. But the gun law violations are serious enough to get him considerable jail time if convicted.
The Associated Press contributed to this article.