Judicial Watch provides a summary of evidence documented in FBI files of the "hardcore" communist ties and activities of the father, father-in-law, and maternal grandfather of President Obama's senior adviser Valerie Jarrett. 

On Jarrett's father, Dr. James Bowman:  

Jarrett’s dad, pathologist and geneticist Dr. James Bowman, had extensive ties to Communist associations and individuals, his lengthy FBI file shows. In 1950 Bowman was in communication with a paid Soviet agent named Alfred Stern, who fled to Prague after getting charged with espionage. Bowman was also a member of a Communist-sympathizing group called the Association of Internes and Medical Students. After his discharge from the Army Medical Corps in 1955, Bowman moved to Iran to work, the FBI records show. [...] JW also obtained documents on Bowman from the U.S. Office of Personnel Management (OPM) showing that the FBI was brought into investigate him for his membership in a group that "follows the communist party line." 

On Jarrett's father-in-law, Vernon Jarrett: 

Jarrett’s father-in-law, Vernon Jarrett, was also another big-time Chicago Communist, according to separate FBI files obtained by JW as part of a probe into the Jarrett family’s Communist ties. For a period of time Vernon Jarrett appeared on the FBI’s Security Index and was considered a potential Communist saboteur who was to be arrested in the event of a conflict with the Union of Soviet Socialist Republics (USSR). His FBI file reveals that he was assigned to write propaganda for a Communist Party front group in Chicago that would “disseminate the Communist Party line among…the middle class.”

JW also notes that the FBI documents show that Jarrett's maternal grandfather, Robert Rochon Taylor, had a business partnership with Stern, the Soviet agent who worked with her father.

JW states that Jarrett's "liberal extremism" has played into her advising of the president over the years. "Faithful to her roots, she still has connections to many Communist and extremist groups, including the Muslim Brotherhood," JW writes. "Jarrett and her family also had strong ties to Frank Marshal Davis, a big Obama mentor and Communist Party member with an extensive FBI file."