Marc S. Dreier on Wednesday sent a confessional letter to the federal judge who will sentence him on Monday (pdf), describing in remarkable detail how he funded the once-admired expansion of Dreier LLP by committing frauds totaling more than $400 million.

Facing a recommendation from the government that he serve the rest of his life in prison but pleading for a measured sentence, Dreier, 59, said his seven-year downward spiral began with a simple theft from a client settlement fund and ended at the point where “I found myself running a massive Ponzi scheme with no apparent way out.”