For 25 years, former Utahn Florian Thayn worked deep in the dark passages of a haunted building: the U.S. Capitol.

She was a historian for the Capitol architect. Part of her job was thumbing through dusty volumes researching the abundant ghost stories that have crept out of the eerie shadows and echoes of the building's dim, windowless, meandering halls.Thayn, who recently retired, says that if even a fraction of the Capitol's ghost stories are true, then it is the most haunted edifice in the nation's most haunted city.

After all, it's hard to go throw a rock in any direction in Washington without hitting a haunted house.

Francis Scott Key - author of the Star Spangled Banner - is said to haunt the often fog-bound Key Bridge over the Potomac River because his house was destroyed for it.

People still say they hear screams from the Octagon, the house where President James Madison lived after the British burned the White House in the War of 1812. It was said to be haunted even back then by a murdered woman.

The ghost of Abraham Lincoln still reportedly visits the White House, often appearing in his old bedroom, with the last sighting reported by Maureen Reagan. President Reagan reported his pet dog would sometimes stop and bark at something invisible there.

But Thayn says none of those tales even comes close to the hauntings at the Capitol.

"It really can be a spooky place, especially at night when there aren't many people around. The halls are dim, there aren't many windows and there's a lot of echoes of things going bump in the night," she says.

"I always left before witching hour, so I never saw any ghosts myself. But all those who preceded can't be wrong, can they? After all, most of their stories were printed and if it's in print, it must be true - right? I do think, though, that many who verified these stories had a strong belief in John Barleycorn (liquor)," she says.

Still, following are some of those stories that are her favorites:

THE DEMON CAT - "The demon cat is the most-often reported phantom in the Capitol," she says. Sightings date back to the days when dozens of cats were placed in the Capitol's halls to control its growing rat and mouse population.

"The demon cat would usually meet someone alone in a dark corridor. It had large yellow eyes that seemed to hypnotize, and it would snarl. It would seem to grow larger and larger until it would make a final lunge toward its victim and then either explode or disappear over the victim's head," Thayn says.She says stories say guards fired guns toward the hissing cat as it disappeared only to find they were shooting into an empty hall. "It was said to appear only on the eve of a national tragedy or the change of administrations." The cat even has a nickname among Capitol workers - "D.C."

JOHN QUINCY ADAMS - "He was the only man elected to the House of Representatives after serving as president," she says. "But he was stricken with a heart attack while giving a speech on the floor about the Mexican War."

He died in a small room behind the old House Chamber - which is now Statuary Hall. "Many maintain that they see him all the time, apparently coming back to finish his speech."

THE BLOOD-STAINED STAIRS - No cleaning agent has ever been able to scrub away the blood of former Rep. William Taulbee, D-Ky., who was shot to death on a stairway leading to the new House chambers in 1890.

"He was apparently involved in a love triangle," Thayn says. Another in the triangle was newspaper reporter Charles Kincaid.

"Kincaid was a small man, only 5-foot-3. Taulbee, who was a former member at the time, was big and known as a mean, demeaning man. They got in an argument, and Kincaid shot Taulbee.

"Judging from the blood, he must have bounced all the way down the stairs. The marble soaked it up like a sponge, and they've never been able to scrub it away," she said. "Kincaid was tried for murder a year later but was acquitted."

Roll Call, a Capitol Hill newspaper, reported stories last year that Kincaid's ghost still haunts the stairway and trips anyone it sees wearing press credentials because he was killed by a reporter. Thayn said, "I never heard that one. But these stories tend to get a little better every time a reporter repeats them."

HENRY WILSON - "He was vice president to Ulysses S. Grant," Thayn said. "He suffered from pleurisy and loved to relax in the large marble bathtubs under the Capitol on the Senate side.

"One day he caught a chill. He developed a cold, and it was fatal. He died in the vice president's office. Many have said they felt his ghost there - that they feel a chill and sense the faint smell of soap or hear sneezes and coughs outside his office.

She said tour guides often tell tourists that if they hear that, to keep on walking because Henry Wilson may have joined the tour.

PIERRE L'ENFANT - "He is the man, of course, who designed Washington. He claimed the government owed him money," she said.

"People have reported a tall, erect man with a roll of plans under his arm walking the halls. He's still apparently trying to get his money."

THE DILIGENT JANITOR - A member of a Capitol cleaning crew died one night with a scrub brush in his hand. His crew was surprised soon thereafter to see he apparently had returned from beyond the grave to continue his cleaning.

"Many say they hear the water and the sloshing of his scrubbing late at night, and that they can still sometimes catch a glimpse of him," Thayn said.

THE STONED WORKMAN - "One workman was supposedly sealed in a wall. People have reported seeing a trowel in a hand passing through the wall," Thayn said.

GEN. JONATHAN LOGAN - "He was a general during the Civil War, who often had to appear before Congress," Thayn said. "He supposedly shows up with a concerned look on his face trying to appear before the Committee on Military Affairs."

She added that when air conditioning was installed in 1929, workers found a sealed room where a preserved horse was found. It looks like the horse on which a statue of Logan is sitting in the middle of Washington's Logan Circle.

THE LIVING STATUES - The statues of famous people from the various states in Statuary Hall are sometimes apparently lively, especially on New Year's Eve.

"One old-timer said he stopped dead in his tracks one New Year's Eve as he saw silhouettes of the statues dance around, and even saw Grant shake hands with (Robert E.) Lee in a strange light," she says. "When he told police, they prescribed rest."

She said one member of Congress in the late 1960s even gave a speech on the House floor saying he was walking through Statuary Hall late at night, when he heard whispers and had a chilly feeling come over him - only to see the statues apparently looking at him.

"He said he later realized it happened at the instant that (former Supreme Court Justice) Abe Fortas resigned," Thayn said.

THE SAD LIBRARIAN - The ghost of a librarian who worked for the Library of Congress was said to appear for years in the Capitol - where his office had been - because he had been suspected of embezzling $20,000.

Thayn said he apparently had not stolen the money, but simply put the $2 that had accompanied books as a copyright fee inside the volumes intending to later record it. "But he died first." She said the ghost stopped appearing once the money began to be found $2 at a time in old books.

THE WORKING LIBRARIAN - Another dead worker for the Library of Congress also has been reported to be seen in his old basement office patiently stamping books - with the "stamp, stamp, stamp" echoing through the halls.

"I got excited about that one because people claimed that they saw from a tag that his name was Mr. Twine. I went through employment records at the Library of Congress, but I couldn't find anybody with that name," Thayn said.

GHOSTLY VIBES IN THE COURT - Some tour guides claim they have a cold chill every time they enter the old Supreme Court chamber in the Capitol. It may come from John Lenthall, who was killed there in the early 19th Century.

Thayn said he was in charge of construction to renovate the room. "He removed the brace for a beam without permission of the architect, and it crushed him."

ABRAHAM LINCOLN, HENRY CLAY, THOMAS HART BENTON - "Lincoln doesn't come around the Capitol as much as he does the White House, but he has been reported there. After all, he was a member of Congress before he was president," Thayn said.

"It fits in with a lot of ghostly stories about him - including how he dreamed that night before he died that he was going to die."

Former speaker of the House Clay and Sen. Benton also have been reported. "Clay shows up a lot," Thayn said.

Thayn said she also saw a Specter from the Senate - Sen. Arlen Specter, R-Pa., that is, who is still alive and well.