The Securities and Exchange Commission is consistently letting fraudsters off the hook, one of its commissioners warns.

Luis Aguilar, one of the five SEC commissioners, late Thursday issued an unusual dissent to the SEC's punishment of an accountant, calling the decisions a "wrist slap at best."

Aguilar said that he worried the case was "emblematic of a broader trend at the Commission where fraud charges ... are warranted, but instead are downgraded" to lesser charges.

The SEC's decisions, Aguilar charged, may be "purposely vague and/or incomplete, and written in a way so as to lead the public to conclude that no fraud had occurred." That can result in people who should have been charged with fraud to continue in the securities business, Aguilar warned.

The case in question concerned a Dallas information technology company inflating its earnings. The CEO and CFO of the company settled with the SEC for $675,000. They were not accused of fraud, however.

Aguilar was appointed by President George W. Bush in 2008, then reappointed by President Obama in 2011.