Johnson's Mexico visit prompted probe

DALLAS, Jan. 8 (UPI) -- The FBI said in a file regarding former first lady Lady Bird Johnson a probe into security risks in Mexico was conducted before her 1966 visit.

The Dallas Morning News said Friday the recently released FBI file on the wife of former U.S. President Lyndon Johnson shows how Mexican communist party activities were investigated ahead of the first lady's planned visit to Mexico in April 1966.

After no security threats were found, Johnson decided to join his wife and made his first visit to a foreign capital during his presidency.

The FBI said in the released file that Johnson, as well as her husband, did receive a death threat in 1967.

"Your grandchildren should be burned to death as you watch," an unidentified individual said in the threatening letter. "Like you no good."

The FBI ultimately determined the first lady and her husband were not in danger despite the letter's threat of violence, the Morning News reported.

The FBI file was released through a Freedom of Information request.