During the past four years, federal judges imposed sentences of one to four years on five defendants in the AIG fraud case that caused more than $500 million in losses; 25 years on Ronald Treadwell for a Ponzi scheme involving a $40 million loss; and 3 1/2 years on former Impath Inc. President Richard Adelson for a $50 million securities fraud.

Those widely disparate sentences don’t make sense, ignore federal sentencing guidelines and are a sign of a potentially very big problem, according to the U.S. Department of Justice. The DOJ wants the U.S. Sentencing Commission to investigate, with special attention to guidelines for fraud and child pornography crimes. But some sentencing experts say it may be something that the commission does not want to examine too closely.