As it turns out, per the research of KGB archives by Allen Weinstein and Alexander Vassiliev in their book from 1999, The Haunted Wood, Samuel Dickstein was a foreign agent in the employment of the NKVD at the time and who the NKVD considered so greedy that they gave him the code of "Crook".
Adding a further twist to this story, Fritz Kuhn, in response to various accusations by Mr. Dickstein on March 11, 1937, openly accused Rep. Dickstein on the same of being a spy, although the accusation was completely baseless and thoroughly unconvincing.
Dickstein, not I, is one of the country's biggest enemies. I think he is a spy for Soviet Russia ... Dickstein is a Jew, born in Russia. I consider myself a better type of citizen than he is.
Sources: The Haunted Wood review http://www.nytimes.com/books/99/01/03/reviews/990103.03persict.html
Wiki article http://en.wikipedia.org/wiki/Samuel_Dickstein_%28congressman%29
and see Henryk's post and link http://forum.axishistory.com/viewtopic.php?f=34&t=60746&start=15