Envelope Laced with Poison Mailed to White House

The U.S. Secret Service says a letter addressed to the White House has tested positive for cyanide, a deadly poison.

The agency, which is charged with protecting the president and other high-ranking officials, issued a statement Tuesday saying the letter was received at a screening facility away from the White House campus the day before. The letter initially tested negative for biological agents, but the agency said further tests returned a “presumptive positive” for cyanide.