Federal counterterrorism officials on Monday raided the suburban Detroit offices of an international Muslim humanitarian organization.
FBI and Joint Terrorism Task Force agents executed search warrants at the headquarters of Life for Relief and Development in the Detroit suburb of Southfield.
The warrants were based on a criminal assertion, but the affidavits in support of the warrants are sealed, William Kowalski, an assistant special agent in the FBI's Detroit office, told the Detroit Free Press.
"The warrants have been signed off by a judge, and it pertains to an ongoing criminal matter," FBI spokeswoman Dawn Clenney told The Associated Press. She did not give additional details.