On a Saturday morning in early December, a group of outsiders dressed in jeans arrived at the J. Paul Getty Trust to carry out a secret plan: copying the computer hard drives in the offices of Chief Executive Barry Munitz without his knowledge.

The outsiders were from Munger Tolles & Olson, a Los Angeles law firm hired by Munitz's bosses, the Getty board, to investigate allegations that senior officials had misspent the nonprofit's funds and acquired looted antiquities.

The decision to secretly copy Munitz's data, carried out with the help of his top aides and the approval of the board chairman, was an early sign of the extent to which Munger Tolles was willing to go to find out how deep the problems ran at the world's richest art institution.

Confidential Getty documents reviewed by The Times and interviews with former senior officials provide a road map of the firm's internal investigation, which led to Munitz's ouster and ongoing negotiations with foreign governments over the return of contested artwork.

The records also show that the attorneys spent a substantial amount of time investigating Munitz's previously unreported use of Getty funds to advance the career of a German art student whom he hired as a "senior advisor" and sponsored as an intern at another museum. They also reviewed his expenditures linked to a Russian researcher whose museum received a Getty grant.

The Getty has declined to disclose whether those expenditures were deemed appropriate. Munitz, through his lawyer, said he was a mentor to both women, as he has been to "students, colleagues and future leaders" over the last 40 years.

"Given these facts, nothing about these professional relationships had anything to do with my decision to resign," Munitz said.

Munitz resigned in February, less than a week after Munger Tolles delivered its findings to the board. He agreed to forgo more than $2 million in severance pay and return $250,000 to settle all claims with the trust.

Munger Tolles has billed the Getty more than $4 million for the review led by Ron Olson, the firm's top corporate trouble-shooter. The money comes on top of $6 million the Getty has spent on lawyers, investigators and public relations specialists over the last five years to disentangle itself from a web of scandals and crises, records show.

Getty officials have not made the results of the Munger Tolles review public, saying it would not be in the interest of the institution, which is still being investigated by the state attorney general and foreign governments.

But the Getty records show that Olson's team spent hours researching the legal exposure of current trustees, who were responsible for overseeing Munitz's compensation and travel.

The attorneys also researched "moral turpitude," a legal term that experts say describes deceit for personal gain and other crimes such as fraud and perjury.

Munitz's contract stipulated that the Getty could terminate his employment for any conduct that "constitutes moral turpitude, or that would tend to bring material public disrespect, contempt or ridicule upon the trust."

Through his attorney, Munitz said that "the moral turpitude clause in my contract was never raised with me."

Olson, in a recent interview, said he had made "a complete report … of the essence of our findings" to the state attorney general's office, which is expected to conclude its own probe of Getty spending in the coming weeks. He added it would be wrong to draw inferences about what the attorneys researched. "Just because we investigate facts or assess legal exposure does not equate to, or even suggest, wrongdoing," he said.

With the attorney general beginning its probe and Munitz under fire for using Getty funds on lavish first-class travel and other questionable purposes, the Getty board hired Olson a year ago to conduct an internal review. Louise Bryson, the board's current chairwoman and a longtime Olson friend, played a key role in the decision, sources say.

Olson billed the Getty $690 per hour and led a team of more than two dozen attorneys, staff and consultants, records show. The lawyers examined hundreds of thousands of documents, interviewed 75 people and even flew to Rome to interview Marion True, the Getty's former antiquities curator now on trial there on charges of conspiring to traffic in looted art.

The attorneys also reviewed 230 trips taken by Munitz from January 1998, when he became the trust's chief executive, through July 2005. They singled out several where Munitz's business justification was weak or where he added official events to trips that originated as vacations with friends, records show.

Those flagged as problematic were cruises to Cuba, Greece, Croatia and Albania with Los Angeles billionaire and philanthropist Eli Broad and others. Other trips included those to Australia, Hawaii and Italy.