MF Global's bankruptcy trustee, Louis Freeh, has refused to turn over some documents to the Commodity Futures Trading Commission (CFTC), which is investigating what happened to an estimated $1.2 billion in missing customer funds, the Wall Street Journal said.

Freeh, a former director of the Federal Bureau of Investigation and who represents MF Global's parent company, has asserted attorney-client privilege in deciding not to release certain documents to the CFTC, according to his office and people familiar with the matter, the Journal said.

The dispute is complicating efforts to learn how the firm lost the customer funds and to return the money to its owners and could slow the investigation, the Journal said, citing people familiar with the investigation.

A spokesman for Freeh's office told Reuters that the trustee's team was cooperating with regulators, law enforcement and Congressional committees and is not aware that our initial desire to preserve the attorney-client privilege has hampered their respective investigations.

To the extent that the authorities express concerns to us that the effort to preserve the attorney-client privilege is hampering their investigations, we of course would be willing to discuss the issue with them and be inclined to waive privilege, the spokesman said.

A spokesman for the CFTC declined to comment the Journal on the story.

The CFTC could not be reached by Reuters for comment after U.S. business hours.

Separately, the New York Times said CFTC is scrutinizing whether CME Group's efforts to verify the safety of customer funds were sufficient. The newspaper cited people briefed on the matter.

CME, which also served as MF Global's primary regulator is the operator of the main exchange where the commodities brokerage firm conducted business.

CME could not be reached for comment after U.S. business hours.

(Reporting by Rachana Khanzode in Bangalore; Editing by Matt Driskill)

Investment