In advance of what promises to be a closely watched hearing Thursday in Tribune Co.’s Chapter 11 bankruptcy case, the U.S. trustee’s office asked U.S. Bankruptcy Judge Kevin Carey to appoint an examiner to investigate charges that Sam Zell’s 2007 leveraged buyout of the Chicago-based owner of the Los Angeles Times.

The move supports a motion filed by a deeply subordinated group of Tribune Co. bondholders represented by Wilmington Trust Co. that has argued that the transaction was an example of “fraudulent conveyance,” meaning the debt-heavy LBO itself rendered Tribune Co. bankrupt from the start.

Tribune Co. also owns Los Angeles TV station KTLA Channel 5 and the Chicago Tribune. An attorney for the U.S. trustee, which is charged with enforcing bankruptcy laws, offered no opinion on the merits of a fraudulent conveyance case but agreed that it was important for an independent examiner scrutinize the evidence.

but Tribune Co. contends that further litigation would only generate more confusion and expense. The company has asked for more time to negotiate a settlement, which would take the potential charges into account.

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