(CNN) -- Despite a report Tuesday of possible hazardous materials at a mail facility at Joint Base Anacostia-Bolling in the nation's capital, no suspicious packages or letters were located, a Defense Intelligence Agency spokesman said
The agency's mail-screening equipment alerted officials to the possible presence of a hazardous substance. Preliminary tests indicated it was a possible biotoxin, officials said earlier.
But after an on-scene investigation, it was determined there was no threat, Lt. Col. Thomas F. Veale, an agency spokesman, said.
The FBI has taken samples and will conduct further testing, he said.
CNN's Carol Cratty and Greg Seaby contributed to this report.