The White House received an envelope this week that tested positive for cyanide.
The envelope, received Monday at the White House Mail Facility, listed a return address for a man who has a record with the Secret Service dating back to 1995, The Intercept reported Tuesday after obtaining an internal law enforcement document that alerted staff about the incident.
"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 staff alert said.
The man listed at the return address was involved in an incident in which he sent a package covered in urine and feces. Over the years he has sent multiple packages; his most recent one was in June 2012 containing multiple mini alcohol bottles.
"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," Secret Service spokesman Brian Leary said in a statement. "The sample was transported to another facility to confirm the results."
Due to an ongoing investigation, Leary said the Secret Service "will have no additional comment."
There were no injuries or exposure concerns, a law enforcement official said, according to CNN.