What terrible secret drove Vincent Foster, the Clintons' personal lawyer, to put a bullet through his head?

When that question was posed in this space last summer ("Was dread of further scandal a triggering cause of the apparent suicide?") Clinton aides blamed Foster's state of mind on the cruel, mean-spirited Washington press corps, with its focus on "travelgate."Questions about a lawyer with a guilty conscience were denounced as ghoulish, the product of a conspiratorial mindset.

We subsequently learned that there was indeed a scandal brewing that involved the Clintons, a go-go banker crony who financed their Whitewater real estate deal and an S&L failure, now under criminal investigation, that cost taxpayers $60 million.

Foster improperly kept the potentially damaging records of that deal in his White House office. Surely crossing his mind after the furor over the abuse of power in travel office patronage was the potential of far greater disgrace or prosecution in a money-and-influence scandal.

From the moment Foster's body was found, White House Counsel Bernard Nussbaum acted to keep those Whitewater files away from prying eyes.

The investigation was confined to the Keystone-Kop Park Police; Clinton lawyers refused to let them or the FBI see papers that might have revealed the suicide motive; and then - secretly - the files were spirited away from the White House to the president's personal lawyer.

When the existence of the hidden file came to light the Clintons stonewalled. Hillary Rodham Clinton, attorney for the rotted-out S&L while her husband was responsible for its regulation, professed not to understand why anybody would be interested in a deal that lost them $60,000. But curiously, the Clintons never took that loss, if it existed, off their income taxes, more strangely, they wrongly took other deductions and the lawyer who worked with Hillary on these returns was Foster.

During the '92 campaign, to cover up the messy record, Foster arranged for a lawyer to hire a Denver accountant to whitewash Whitewater; the Patten, McCarthy report omitted the largest transaction undertaken by Clinton's partnership - a half-million-dollar land purchase from a paper company to which Gov. Clinton granted tax breaks.

After the mean, insensitive press raised a ruckus to produce the Whitewater files, Clinton was forced to agree to "cooperate" with the investigation of the bank's taxpayer rip-off. He directed his personal lawyer to turn the Whitewater files over to the Justice Department - a far cry from public disclosure.

But a curious lassitude overtook Clinton Justice. The files were not turned over forthwith; instead we were told they were being "catalogued," which the White House said would take "a couple of weeks."

Only Wednesday, as this and other denunciations were being written, did one box containing Foster's files, and four boxes of backup to the accountants' whitewash, begin to get delivered.

Were the files so voluminous to require "cataloguing"? Can we be sure the documents did not get the treatment given the so-called suicide note, which appeared belatedly in 27 pieces, not one with a fingerprint, and with the signature space missing?

If I were Louis Freeh, the new FBI director chosen by Nussbaum and known as "Bernie's Good Deed," I would follow up by searching for a Foster safety deposit box or home strongbox, and would demand that Justice seek subpoenas to force the Clintons and their former law partners and accountants to produce all other relevant papers.

What could explain the Clintons' document shell game that has been going on since the discovery of Foster's body?

Actions taken by lawyer-investor Hillary Clinton in 1988, when she requested power of attorney to "manage and conduct all matters related to Whitewater Development Corp." may soon come under the statute of limitations.

Special in-house counsel? Not unless it's Robert Morgenthau; better to use this pressure for House passage of the Independent Counsel Act.

No politician is so stupid as to try to hide something when there is nothing to hide. The Clintons' pattern of behavior in Whitewatergate is that of wheeler-dealers with something serious to hide. Let's hope it's only politically embarrassing.