Letter Sent To White House Contained Cyanide

According to the Secret Service, someone sent the White House a letter containing cyanide. Testing was performed on an envelope that was received on Monday and appeared to contain an "unknown milky substance." Preliminary biological testing results gave a negative response, but chemical testing results showed a "presumptive positive" for cyanide. Secret Service spokesman Brian Leary said the sample was sent to another location in order to confirm the results.

Luckily, a law enforcement official said there were no injures or concerns about exposure to the chemical for the mail room worker who opened the letter. According to The Intercept, an internal law enforcement alert read:

An envelope containing an unknown milky substance, in a container wrapped in a plastic bag, received at the White House Mail Screening Facility, tested positive for Cyanide.

The Intercept reports that the envelope included a return address from a man who has had previous run-ins with the Secret Service before. That record, which dates back to 1995, includes allegedly sending a package covered in urine and feces. The most recent interaction he had with the White House was when he sent a package filled with mini alcohol bottles.

Sources told ABC News that charges against the sender are possible, depending on whether or not the substance was actually cyanide or another hazardous chemical.