Several CDs marked with slain radical cleric Anwar al-Awlaki's name were seized from the home of a Detroit man who was arrested after buying five grenades from an undercover federal agent, according to a sealed search warrant obtained by The Detroit News.

Federal authorities would not disclose what the CDs contained, but listed them plus seven rifles, two assault rifles, a shotgun, handguns, thousands of rounds of ammunition, computer equipment and cellphones that were found at Sebastian Gregerson's west side home, the newspaper reported Saturday.

Gregerson, 29, is charged with possessing an unregistered destructive device. He was arrested Sunday in Monroe, southwest of Detroit.

Court records allege Gregerson spoke about carrying out an unspecified attack, but his defense attorney, David Tholen, has said the government is exaggerating Gregerson's threat.

Tholen said earlier this week that Gregerson is just a survivalist. However, prosecutor Cathleen Corken told federal Magistrate Mona Majzoub on Thursday that Gregerson appeared to be preparing for violent acts. She called him a dangerous man.

Anwar Al-Awlaki, a radical American-Yemeni cleric, was influential among militants living in the West. His English language Internet sermons called for jihad, or holy war, against the United States. Al-Awlaki was killed in 2011 in Yemen by an unmanned drone.

The FBI has said that a U.S. soldier sentenced to death in the 2009 slayings of 13 people at the Fort Hood military base in Texas sent numerous emails to al-Awlaki. And convicted terrorist Umar Farouk Abdulmutallab, who is serving a life sentence for trying to blow up a Detroit-bound airliner in 2009, trained under al-Awlaki.

"When you look through most of the cases of individuals who get arrested for terrorism charges, the vast majority had al-Awlaki on their laptops," Seamus Hughes with the George Washington University's Program on Extremism told the newspaper.