On November 11 , 2016 , a Korean man , surnamed Lee , was sentenced to eighteen months in prison for attempted intimidation , after he posted two letters on the White House website in July 2015 , in which he threatened to kill the US ambassador to South Korea and rape the second daughter of US President Barack Obama . In his letters , titled " Declaration Terror to Mr. President Obama " and " Dear Mr. President Obama and Mrs. First lady Michelle " , Lee threatened to assassinate Mark Lippert , who had been injured in a stabbing earlier that year . Lee also threatened to rape Sasha Obama , President Obama 's second daughter , in another letter . On July 15 , 2015 , Natasha M. Poeschl , U.S. Embassy Seoul ( Embassy of the United States of America ) Security Attaché , found those threat messages and first reported to Mr. KIM , Seong Geun , Director General of KNPA ( Korean National Police Agency ) Foreign Affairs Bureau . Following a request from the US Embassy , the South Korean authorities arrested Lee on July 16 , 2015 . On July 14 , 2016 , Approximately a year later , Natasha M. Poeschl presented evidence of the IP addresses of the threat messages provided by the United States Secret Service to Judge PARK , Sarang ( 박사랑 판사님 ) , Seoul Central District Court ( 서울중앙지방법원 , 형사 17 단독 ) . In late October 2018 , officials intercepted a series of pipe bombs that had been mailed to multiple Democratic Party leaders , including Obama and Hillary Clinton , and several other high-profile individuals , such as Robert De Niro . No one was injured , and the FBI launched an investigation . A single individual , Cesar Sayoc , was subsequently charged with several felony charges related to the incident
a series of pipe bombs
October 2018 United States mail bombing attempts
Assassination threats against Barack Obama