An envelope laced with cyanide was mailed to the White House, the Secret Service revealed Tuesday.
"On Monday 3/16/15, an envelope was received at the White House Mail Screening Facility. Initial Biological testing was negative; however, on 03/17/15, the chemical testing returned a presumptive positive for cyanide," said Secret Service spokesman Brian Leary in a statement to CNN.
Secret Service confirms an envelope received at the White House has tested positive for cyanide pic.twitter.com/APc0m4GLc5
— Jon Passantino (@passantino) March 18, 2015
The envelope contained an "unknown milky substance" inside a container and plastic bag. There are no known injuries or exposures, CNN reports.
The incident was first reported by The Intercept. The envelope included a return address to a man who had previous incidents with the Secret Service dating back to 1995.
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Gavin Stern is a national digital producer with the Scripps National Desk.