US officials have intercepted an envelope addressed to Donald Trump that contained the deadly poison ricin.
The letter was intercepted at a government facility that screens mail addressed to the White House and the president.
A preliminary investigation indicated it tested positive for ricin, a poison found naturally in castor beans which can be extremely lethal if inhaled or injected.
Federal investigators are working to determine where the enveloped originated from and who posted it. It is believed that the letter was sent from Canada, a law enforcement official told the New York Times.
The FBI, the Secret Service and the US Postal Inspection Service are leading the investigation.
In a statement, the FBI confirmed agents were looking into ‘a suspicious letter received at a US government mail facility’ and that there is ‘no known threat to public safety’.
Deadly ricin has previously been used to target American politicians through the mail
A Navy veteran was arrested in 2018 and confessed to sending envelopes to Mr Trump and members of his administration that contained the substance from which ricin is derived.
Authorities said the man, William Clyde Allen III, sent the envelopes with ground castor beans to the president, FBI director Christopher Wray, along with then-defence secretary Jim Mattis, then-CIA director Gina Haspel, Admiral John Richardson, who at the time was the Navy’s top officer,m.
The letters were intercepted and no one was hurt.
In 2014, a Mississippi man was sentenced to 25 years in prison after sending letters dusted with ricin to President Barack Obama and other officials.