What can you say about a 4 1/2-year-old cat that spied?

That he's quiet, polite and neutered? That he loves Tender Vittles -- and sheds?

"Sir, I have nothing to say about the cat," was how U.S. Attorney Joseph diGenova responded yesterday.

DiGenova was collared after a bond hearing for one of the cat's owners, Anne Henderson-Pollard, who is accused of helping her husband, Jonathan Jay Pollard, in an alleged scheme to sell American secrets to Israel. She, like her husband in an earlier hearing, was denied bond and sent back to jail.

Ever since the morning of Nov. 21, when FBI agents caught the couple driving their 1980 Mustang into the Israeli Embassy -- apparently seeking sanctuary for themselves and their cat, who was stuffed into a tote bag, some of the city's spy buffs have been burning to know just who let the cat out of the bag.

In fact it was the FBI -- which arrested Pollard at the Israeli Embassy and his wife a few days later -- that let the cat out. When agents looked into Henderson-Pollard's purse, they found the cat's vaccination certificate.

"We did not take custody of the cat," FBI Special Agent Eugene J. Noltkamper testified in court last week.

Sources have since revealed that the cat's name is Dusty. But other feline mysteries are not so easily solved, especially when the feline under investigation is mixed up with international intrigue.

For instance, what sort of cat is this Dusty?

"It's an alley cat," said Bernie Henderson, father of the accused, who has been caring for the pet in the owners' absence. "I'm not a cat person."

"It looks like a Siamese," said Tim Dane, one of the couple's neighbors in their Dupont Circle apartment building.

"I'd say it was more of a Persian," guessed another neighbor, Stephen Figliozzi. "A little fat white one."

Anything suspicious about Dusty's habits?

"A very polite cat, certainly not a screecher. He's friendly," said Figliozzi, the erstwhile super of the building, who has been to their apartment on several occasions. "I have to say, they could have changed the cat box a couple of times."

"The cat was always howling and playing a lot of loud records," ventured Dane. "No, really, the cat was a perfect neighbor. It wore a trench coat and a diamond-studded collar. No, really."

Would Dusty have been welcome in Israel?

"I'll have to check that for you," said the Israeli Embassy's press counselor, Yossi Gal, ever eager to be of help in this matter. "I guess dogs are more popular than cats."

In truth, Dusty is probably not a spy. For one thing, it would be exceedingly difficult for him to pass on secrets or even nonsecrets.

"He never makes any noise at all," said John Henderson, Henderson-Pollard's 19-year-old brother, who has known Dusty since his kittenhood in Allentown, Pa. "That's because he has no vocal cords."