Authorities think the eighth suspect is in Pakistan, according to a law enforcement official who spoke on condition of anonymity because they were not authorized to discuss the investigation. U.S. Attorney George E.B. Holding declined to discuss the suspect's whereabouts but said the public should not be worried.
"Federal authorities hope to have him apprehended shortly," Holding said. Holding wouldn't identify the person, and the defendant's name is redacted from court papers.
The indictment said the person went to Pakistan in October to "engage in violent jihad."
Investigators arrested seven men involved in the group Monday, accusing them of military-style training at home and plotting terror attacks abroad. The men purchased several weapons over the past year, and in June and July, three of them went to private land in north-central North Carolina to practice "military tactics," according to the indictment.
"It's clear from the indictment that the overt acts in the conspiracy were escalating," Holding said.
The men do not appear to be connected to any larger terror group or any plot against U.S. targets, CBS News correspondent Bob Orr reported.
The indictment names Daniel Patrick Boyd, 39, as the group's ringleader, and authorities said he recruited others to join his cause. Prosecutors have said Boyd was frustrated by the moderate mosques in the Raleigh area and began holding private prayer services in his home.
Boyd's wife, Sabrina, said in a statement issued through the Muslim American Society in Raleigh that the charges have not been substantiated.
"We are ordinary family," she said. "We have the right to justice, and we believe that justice will prevail. We are decent people who care about other human beings."
The Boyds lived at an unassuming lakeside home in a rural area south of Raleigh and had a family-operated drywall business.
Neighbor Jim Stephenson said he often saw the Boyd family walking their dog.
"We never saw anything to give any clues that something like that could be going on in their family," Stephenson said of the indictment.
Boyd's two sons, Zakariya, 20, and Dylan, 22, were also named in the indictment. The others charged are Anes Subasic, 33; Mohammad Omar Aly Hassan, 22; and Ziyad Yaghi, 21. Hysen Sherifi, 24, a native of Kosovo and a legal U.S. resident, was also charged. He was the only non-U.S. citizen arrested.
The seven men appeared in court Monday, charged with providing material support to terrorism and "conspiracy to murder, kidnap, maim and injure persons abroad." They're scheduled to appear again Thursday for a detention hearing.
No attorneys for the men were listed in court records. If convicted, they could face life in prison.
In 1991, Boyd and his brother were convicted of bank robbery in Pakistan. They were also accused of carrying identification showing they belonged to the radical Afghan guerrilla group, Hezb-e-Islami, or Party of Islam. Each was sentenced to have a foot and a hand cut off for the robbery, but the decision was later overturned.
Their wives told The Associated Press in an interview at the time that the couples had U.S. roots but the United States was a country of "kafirs" Arabic for heathens.
Sabrina Boyd said in her statement that her husband was in Afghanistan fighting against the Soviet Union "with the full backing of the United States government."
It is unclear when Boyd and his family returned to the United States, but in March 2006, Boyd traveled to Gaza and attempted to introduce his son to individuals who also believed that violent jihad was a personal religious obligation, the indictment said. The document did not say which son Boyd took to Gaza.
The indictment said some of the defendants took trips to Jordan, Israel and Pakistan to engage in jihad, but only discussed the results of one of those trips. After traveling to Israel, Boyd and his two sons returned to the United States in July 2007 "having failed in their attempt to engage in violent jihad," according to the documents.