Here is Klein's wiki page, heavily propagandized.

Among other scandals, Klein was a central player along with Senator Owen Brewster (Maine) and Juan Trippe (owned Pan Am) to steal TWA from Howard Hughes in the late 1940's.

Brewster sicced J. Edgar and the FBI on Hughes. By chance, during the show-trial senate investigative hearings, which were supposed to be a public coup de grace of Hughes, Senator Claude Pepper (Florida) just happened to walk in on Klein and Trippe strategising with Brewster in Brewster's senate office.

Pepper let Drew Pearson and his young stringer, Jack Anderson (Washington Merry-Go-Round syndicated columnists) know about the meeting and the subsequent newspaper exposure ended the hearings. Hughes kept TWA. The public exposure of the Klein/Trippe/Brewster triumvirate and how they had conspired to destroy Hughes in order to take over TWA marked the beginning of the end of Brewster's power in the senate. Klein and Trippe emerged unscathed.

You can see a dramatization of portions of the hearings in the film "AVIATIOR" (2004) starring Leonardo DiCaprio. Scorsese did not include the fact of the Klein collaboration in the film. The Trippe / Brewster collaboration, however, is well represented. Recommended watching.

https://youtu.be/tWAJcNp7dgQ?t=192 (time stamped / watch 1 min, 20 sec)

For giggles hit view history at the top of Klein's wiki page and scroll down to the very first version of the page in 2012 and note who Klein claims to have as an ancestor.

https://en.wikipedia.org/wiki/Julius_Klein