Its been rumored for the longest time.
Note, he won't release any of his academic records. Now maybe he was a poor student (he has said as much in his own book), but at law school, its pretty safe to say he must have grades (leftist teacher, leftist student, blah blah blah), but he won't release any of this stuff, and its quite weird.
He won’t release it because he probably barely passed. If records are released they will be scrubbed clean and show a straight A student. I’m willing to bet on it.