Halper

https://www.washingtonpost.com/politics/who-is-stefan-a-halper-the-fbi-source-who-assisted-the-russia-investigation/2018/05/21/22c46caa-5d42-11e8-9ee3-49d6d4814c4c_story.html?noredirect=on&utm_term=.b6706d79da11

Father-in law Robert S. Cline worked alongside President John F. Kennedy during the Cuban missile crisis in 1962 and mentored Halper, introducing him to associates in the intelligence and political worlds, according to numerous people familiar with their relationship.~Washington post

https://spartacus-educational.com/JFKclineR.htm