A federal judge in Boston recently blocked efforts by plaintiff lawyers to obtain valuable audit documents created during a company’s internal investigation—a supportive but sobering reminder that in the post-Sarbanes-Oxley age of multiple investigations by audit committees, regulators and civil litigants, companies must use care to ensure sensitive information uncovered during internal probes doesn’t end up in litigious hands.

The case, In re Polymedica Corporation Securities Litigation, involves a report prepared by PricewaterhouseCoopers, which had been retained by Polymedica’s outside law firm to explore questions that had arisen in a Securities and Exchange Commission probe of possible financial irregularities.