U.S. Senator Charles Grassley asked the Securities and Exchange Commission to answer allegations that the agency destroyed files from initial investigations of firms including Goldman Sachs Group Inc., SAC Capital Advisors LP and Bernard Madoff Investment Securities LLC.

Grassley, the top Republican on the Senate Judiciary Committee, made the request in a letter to SEC Chairman Mary Schapiro dated yesterday, citing claims by an agency employee that more than 9,000 such files have been purged. The Iowa lawmaker asked Schapiro to explain whether the SEC routinely destroys documents related to so-called matters under investigation that are dropped in their initial phases.

“It doesn't make sense that an agency responsible for investigations would want to get rid of potential evidence,” Grassley said in a statement. “If these charges are true, the agency needs to explain why it destroyed documents, how many documents it destroyed over what timeframe, and to what extent its actions were consistent with the law.”