It appears the latest potentially poisoned letter was sent to the headquarters of the Defense Intelligence Agency, located at Joint Base Anacostia-Bolling in Southeast Washington.

U.S. Army Lt. Col. Thomas F. Veale said in a statement to The Washington Examiner that DIA security “detected a potentially harmful substance” Tuesday morning as it screened the mail.

Preliminary tests showed “possible biological toxins,” and precautions were taken.

Veale said DIA is operating normally and won’t comment further until the investigation is completed.

Earlier Tuesday, Senate Majority Leader Harry Reid, D-Nev., told reporters that Bolling was the location of an incident involving ricin, a deadly substance that can kill even if just a speck is ingested.

Federal officials have released a Mississippi man who was arrested last week after ricin-tainted letters were sent to President Obama, Sen. Roger Wicker, R-Miss., and a judge. Investigators could find no evidence tying the man to the attacks.

DIA describes itself as “a major producer and manager of foreign military intelligence” for the Defense Department and intelligence community.