Federal law enforcement intercepted a package addressed to President Donald Trump that contained ricin this week, CNN reports. The FBI and Secret Service are now reportedly investigating. Terrorists and authoritarian governments, notably Russia, have made use of ricin to poison enemies in several high-profile cases, including letters sent to the Pentagon in 2018 and addressed to Defense Secretary James Mattis. The toxic compound can induce a range of painful symptoms, from nausea and vomiting to liver and kidney failure.