According to them, on Monday, an envelope containing an ‘unknown milky substance, in a container wrapped in a plastic bag,’ showed up at the White House Mail Screening Facility. Though initial biological testing yielded negative results, chemical testing returned ‘presumptive positive’ for cyanide on Tuesday.
Secret Service spokesman Brian Leary in a statement to CNN said the sample was transported to
another facility to confirm the results and that the Secret Service will have no further comment because the investigation is ongoing.
There were no injuries or exposure concerns for the person at the mail sorting facility who opened the letter, added a law enforcement official.
An alert identified the return address on the envelope as that of a man with a previous history of incidents with the Secret Service dating back to 1995, Intercept reports. The man allegedly once sent a package to the White House covered in feces and urine. In a 2012 incident, the man sent a package to the White House containing mini alcoholic beverages.
