He stated on the application that he had never used another name the the one he was using....IIRC it was one of the charges made when the people of Illinois started impeachment procedures (While he was a Senator).
You’ll find the complete information on this thread. (sorry don’t have time tonight to look up ...Thinks it’s in the first 200 posts.
http://www.freerepublic.com/focus/f-bloggers/2151323/posts
Check out the link posted above you’ll find answers to a lot of questions there. If you have more questions regarding CPUSA and BO links to people involved I’ll try to remember the freeper who has it posted on his page.