Seeking federal prison records of Sigmund Rand

My great uncle, Sigmund Rand, was a very big deal in the small world of Rhode Island bootleggers. I've found articles about his case and his sentence.  Allegedly, he was sentenced to two years in Atlanta's Federal Penitentiary. I'm sure he was sentenced, but I can find no records.  I'd really like to find transcripts from his trial - I have no idea how to start looking for this info either. Any thoughts on finding out more?  Thanks!  See article in The Boston Globe, Boston, Massachusetts, 23 Jan 1928, Mon  •  Page 24