"Only one, maybe two" staffers at "48 Hours Mystery" have contributed to the reported $100,000 defense fund for suspended "48" producer Joe Halderman, says Susan Zirinsky, executive producer of the CBS newsmagazine.

In her first public comments since Halderman's arrest Oct. 1 on charges of attempted grand larceny, Zirinsky said yesterday that the hard-charging producer had raised the bulk of the money "from family and friends, not from people in the shop."

That was all Zirinsky said. Like everyone at CBS, she is on media lockdown about the case. No mystery there. "Late Show" host David Letterman, the target of Halderman's alleged $2 million extortion try, is a cash cow for CBS.

Halderman's attorney, Gerald Shargel, argued in court yesterday that his client is guilty of no crime and that charges should be dropped. Halderman was only trying to sell a screenplay to Letterman, Shargel said, not shake him down about his intra-network sexual liaisons.

Letterman's attorney, Daniel J. Horwitz, labeled it "classic blackmail," not a business transaction. Both sides said they would go to trial, if necessary. The judge is expected to rule in January.

Meanwhile, Halderman's suspension went from paid to unpaid about two weeks ago, CBS sources confirm. Reason? He broke the morals clause in his contract, they say.

While current CBS employees aren't talking, several alums are, including Marcy McGinnis, who worked with Halderman when she ran the London bureau from 1992 to '97. She considers him a friend.

"Joe's a very, very good producer with a big personality," says McGinnis, associate dean of the School of Journalism at Stonybrook. "He was always the guy going to the bad places, the hell holes. No matter what the story was, he'd go, get the goods and deliver on deadline."

Within CBS, Halderman is described as a "cowboy producer;" someone with great instincts and skills who lives on the edge.

McGinnis says she offered to pitch in for Halderman's bail but was told it wasn't needed. She's not so sure about the defense fund -- that's cash she wouldn't get back. "I don't have a huge amount of money. I have to be more careful with it." Also, she hasn't been asked, she says.

Like many of her former colleagues, McGinnis continues to be "flabbergasted" by the Halderman drama.

"I told my parents it would be like them waking up some morning and hearing that I had been accused of extortion."