Alan Shore, embezzler?

Alan Shore from Boston Legal and The Practice was sometimes described as having embezzled money from a previous job. Have any details been given about this?

It seems out of character for him. He was always shown as a compassionate and moral person, by his own standards of morality. He broke a lot of rules, and a few laws, but they were all about correcting an injustice for other people. None of them were about greed. In fact on one occasion he spent tens of thousands of dollars of his own money to compensate a client who lost her case through the firm's negligence. I just don't see him as a thief.

I'm pretty sure that the actual details of the embezzlement were never given on either show. But did David E. Kelley have a backstory that covered it? Has he ever provided details?

And, note, Alan directly admits to the embezzlement.