The Federal Bureau of Investigation (FBI) and Secret Service are probing the matter.
Authorities are on the hunt for the suspect who sent a package to the White House addressed to Donald Trump that contained a poisonous substance.
It was reported that two tests conducted on the package confirmed the presence of ricin, a highly toxic compound extracted from castor beans that has been used in terror plots.
All mail for the White House is screened at an offsite facility before being delivered.
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The Independent has reached out to the White House for comment. Two tests confirmed the presence of ricin, a naturally growing poison bean that can be ground up and unsafe if ingested or injected, according to experts. If ingested, injected or inhaled, it causes nausea, vomiting and internal bleeding of the stomach and intestines.
No known antidote exists for ricin.
Ricin is produced by processing castor beans. If a person is exposed to ricin, death can take place within 36 to 72 hours, depending on the dose received, according to the US Centers for Disease Control and Prevention (CDC).
In 2014, a MS man was sentenced to 25 years in prison after sending letters dusted with ricin to then-president Barack Obama and other officials.