The White House has received poisonous cyanide packed in an envelope carrying the address of a man who had earlier sent a similar package covered in urine and feces to the US president’s official residence, according to the US Secret Service. “On Monday March 16, an envelope was received at the White House Mail Screening Facility. Initial Biological testing was negative; however, on March 17, the chemical testing returned a presumptive positive for cyanide,” Secret Service spokesman Brian leary said in a statement yesterday. “The sample was transported to another facility to confirm the results,” a statement said.