Intended for Donald Trump, the famous envelope containing poison would have been sent from Canada, according to what the Royal Canadian Mounted Police (RCMP) told Global News.
“Preliminary information from the investigation suggests the letter originated in Canada,” said the RCMP, which received a request for cooperation from the Federal Bureau of Investigation (FBI) from the United States.
American media had already put forward Canada as the origin of the envelope.
The RCMP have confirmed that they will work with the FBI, but decline to comment further.
Inside the envelope, the FBI confirmed they found ricin, a poisonous substance.
The envelope was intercepted this week before reaching the US president in the White House.
Ricin is the most violent poison in the plant kingdom, 6,000 times more powerful than cyanide. It is a deadly substance if swallowed, inhaled or injected, and for which there is no antidote.