A letter containing the poison Ricin was intercepted before arrival on President Donald Trump’s desk for the second time, according to law enforcement officials.

The New York Times reports that a package containing the poison and addressed to the President was intercepted earlier this week and is undergoing investigation by both the FBI and the Secret Service. It is believed the package came from Canada.

This marks the second time a poisoned letter was sent to the President and intercepted due to the practice of mail being sorted and screened at offsite facilities before arriving at the White House.

Back in 2018, envelopes containing the poison were sent to not only the President, but Defense Secretary Jim Mattis and top Navy officer Adm. John Richardson as well. A 39-year-old Navy veteran named William Clyde Allen III was later arrested in Logan, Utah after he confessed to sending the letters, KUTV reported.

He was later indicted on charges of mailing a threat against the President, five counts of mailing threatening communications to an officer or an employee of the United States, and one other count of threatening to use a biological agent and toxin as a weapon.

The President is not the only one in the Oval Office to have been sent threatening mail containing ricin or another poison, with former President Barack Obama also receiving threatening mail with the substance. The New York Times reports that in 2013, a Mississippi man sent letters to both the President and a Republican senator that were intercepted. Meanwhile, in 2014, Shannon Richardson, an actress, was sentenced to 18 years in federal prison for mailing letters to both then-President Obama and then-New York City mayor Michael Bloomberg in May 2013.

Ricin is a highly toxic compound that can be extracted from castor beans. According to the CDC, if ingested, it can cause nausea, vomiting, internal bleeding of the stomach and intestines, failure of the liver, spleen and kidneys and death by collapse of the circulatory system.

US President Donald Trump speaks during a campaign rally at the Minden-Tahoe airport in Minden, Nevada on September 12, 2020
US President Donald Trump speaks during a campaign rally at the Minden-Tahoe airport in Minden, Nevada on September 12, 2020 AFP / Brendan Smialowski