The american anti communist crusade intensified in the late 1940s when the government began their investigation of a former state department official who had worked closely with fdr. who was this government official

This government official was Alger Hiss.

Explanation:

Alger Hiss was an American government official who was accused of being a Soviet spy in 1948 and convicted of perjury in connection with this charge in 1950. Before being tried and convicted, he participated in the establishment of the United Nations Organization as much as US Department of State official as a UN official. In his later life, he worked as a lecturer and author.

In the summer of 1948, Hoover leaked the case to Republican Richard Nixon, then a member of the House Un-American Activities Committee.

Hiss was charged on August 3, 1948. Whitaker Chambers, a former communist, claimed to have hidden microfilms that Hiss had handed him in an empty pumpkin. Pumpkin papers became an everyday expression and Chambers book was a bestseller.

Hiss served five years in prison, but throughout his life he continued to maintain his innocence.

which time period is this? or is this story fictional, i'm going to need more info to answer this question