A point oft-repeated today but worth repeating again: How did a guy who made his bones prosecuting corporate criminals get so sloppy with the evidence of his own malfeasance? Every john knows you always pay cash. Always.

Or so I hear.

The federal investigation of a New York prostitution ring was triggered by Gov. Eliot Spitzer’s suspicious money transfers, initially leading agents to believe Spitzer was hiding bribes, according to federal officials…

Client 9 … is alleged to have paid for the woman’s train tickets, cab fare, mini bar and room service, travel time and hotel.

The suspicious financial activity was initially reported by a bank to the IRS which, under direction from the Justice Department, brought [in] the FBI’s Public Corruption Squad.

“We had no interest at all in the prostitution ring until the thing with Spitzer led us to learn about it,” said one Justice Department official.

Spitzer, who made his name by bringing high-profile cases against many of New York’s financial giants, is likely to be prosecuted under a relatively obscure statute called “structuring,” according to a Justice Department official.

Structuring involves creating a series of financial movements designed to obscure the true purpose of the payments.

His family’s worth millions. If he’s hot to play with hookers, why not grab a few fistfuls of dollars from the coffers and pay them with that? In fact, not only was he moving money around to pay them, he was pre-paying them according to the FBI affidavit — $4,300 on February 13 instead of the $2,700 that that night’s “services” cost him. I guess he figured that fewer, larger payments were less noteworthy than smaller, more frequent ones?

Here’s the Times’s account of his tryst with “Kristen,” replete with payment to Qat, and here’s the master article with running updates, now featuring the link to someone named George Fox:

The law enforcement official said that several people running the prostitution ring knew Mr. Spitzer by the name of George Fox, though a few of the prostitutes came to realize he was the governor of New York.

Mr. Fox is a friend and donor to Mr. Spitzer. Asked in a telephone interview Monday whether he accompanied Mr. Spitzer to Washington on Feb. 13 and Feb. 14, Mr. Fox responded: “Why would you think that? I did not.”

Told that the Room 871 at the Renaissance Mayflower Hotel was registered in Mr. Fox’s name but with Mr. Spitzer’s Fifth Avenue address, Mr. Fox said, “That is the first I have heard of it. Until I speak to the governor further, I have no comment.”

Exit question one: Fox surely knew, right? Exit question two: Resignation tonight, do you think, or not? The big A’s betting — no.