Dressed in snug pants and a sweater, Judith Katherine Exner, 41, sat on the gold brocade couch of the $30,000 motor home she shares with her golfer husband in San Diego. She looked up at a large spice rack, containing 50 jars, on the wall of her tiny kitchen. "That," she says contentedly, "is my proudest possession."

Fifteen years ago, blue-eyed, dark-haired Katherine Exner (as she calls herself) did not seem like much of a candidate for such blissful domesticity. She was a 26-year-old divorcée carrying on simultaneous romances with Chicago mafioso Sam Giancana and his dapper protégé John Roselli. These associations now have come back to haunt her and so has an even more intriguing one—with John F. Kennedy.

At 10:30 on the night of Feb. 7, 1960, at a dinner table in the Sands Hotel's Garden Room in Las Vegas (as Katherine's lawyer Brian Monaghan tells it), she was introduced to the then Senator Kennedy. He knew her as Judith Campbell. She was a guest of Frank Sinatra, who was performing at the hotel and filming a movie called Ocean's 11. There were about a dozen guests at the dinner, Monaghan says, including Kennedy's brother Ted and his brother-in-law Peter Lawford.

Katherine saw Kennedy frequently after that, in and out of the White House. "To me he was just Jack Kennedy, not the President," she says, looking evenly at her husband. "He certainly wasn't the highlight of my life." She adds: "It's unfortunate it has all come out. Everyone should be concerned about how history treats our Presidents, but I think I should have some rights also and not be a sacrificial lamb." Many of JFK's inner circle, including secretary Evelyn Lincoln and aide Dave Powers, have denied ever meeting Katherine. "That's just nonsense," she says. "I didn't sneak into the White House. When I went in during the day, I went when a great many people were around. It certainly was no secret that I was there. My name had to be taken two or three times before I got in."

Her husband, Dan Exner, 28, wryly defends her: "She didn't sneak in in a laundry basket or wear a disguise."

"No," Katherine agrees, "but I may start wearing one now."

The source of her worry is the underworld. She hopes to write a book proving that she knew nothing of mobster Giancana's operations. She has not forgotten that Giancana was gunned down before he could tell a Senate committee what he knew about the alleged Mafia-CIA connection.

Before she was subpoenaed by the committee last September, Katherine and her husband Dan had enjoyed three years of near-anonymous companionship. "I wouldn't go across the street without her," he says gazing fondly at Katherine (whom he calls "Kate"). "We have no secrets. As far as I'm concerned, she hasn't done a damn thing wrong." He is a muscular 5'9", 165-pound pro golfer based in San Diego. He wants to go on the tour, but recently he hasn't picked up a club.

Her sudden notoriety has ended their modest social life. On a recent outing, she was recognized in a restaurant and paged to the telephone. Dan went instead, found no one on the line and heard fellow diners snickering. The Exners stay at home now.

Katherine's own early years were, she says, "ordinary." Daughter of a Los Angeles architect, she was raised in a close-knit family of five children and educated by nuns. At 18 she married Hollywood actor William Campbell. It lasted six years. From then on she lived as a liberated young divorcée, took up painting and met Giancana. She last saw him in 1964.

Katherine says bravely she and Dan would be safe from the underworld if "speculation stops about information I don't have." But it hasn't, and they both have the jitters. When an interviewer's tape recorder shut itself off with a noisy click, Dan jumped from his chair. "Don't worry," smiled Katherine, "if they come to get you, you'll never hear a thing."