A court-appointed examiner in the US has released a document on the collapse of the Lehman Brothers investment bank, suggesting some former executives could face criminal charges.

The report by Elizabeth Nowicki, a former lawyer with the Securities and Exchange Commission, is now likely to set the ground rules for charges under securities fraud laws.

In the document, criminal liability issues are discussed, with a section devoted to executives who sent e-mails referring to how Lehman could hide its liabilities.

A dozen former Lehman executives, including Richard Fuld, the former chief executive, have already been subpoenaed in federal grand jury investigations.