Police at the Library of Congress say Charles Merrill Mount, accused of possessing stolen historical documents, was shielded from routine inspections and given a separate office that was not subject to police scrutiny.

Mount, according to a statement prepared by Library of Congress police, was "rarely seen" using the Manuscript Reading Room, where scholars study the library's historic collections. And when he did enter or leave the Reading Room, the police said, he was such a fixture at the library that staff members often vouched for him -- so that police officers posted at the Reading Room security desk refrained from inspecting or searching him.

"Police officers were told by staffers that 'he's okay' or 'he has special staff privileges,' meaning he met with their approval and was not required to be inspected," said the statement, copies of which were sent to The Washington Post.

Nancy Bush, a spokeswoman for the library, said yesterday that Mount had no special access to historic documents and that his research papers "were given as much scrutiny as anyone else's."

There were no signatures on the police statement, but a Library of Congress source said it represented the views of police assigned to the day and night shifts at the Manuscript Reading Room in the library's Madison Annex.

The statement was issued at a time when library police, a small, independent security force, have become increasingly sensitive to security issues raised in the wake of the alleged disappearance of rare documents from the library and the National Archives.

Mount, an art historian and portrait painter, was arrested twice last month after FBI agents discovered more than 200 historic documents in his possession here and in Boston. He has asserted his innocence, saying that the documents are his and have been in his possession for 25 years.

Mount, according to the statement, was never seen entering or leaving the reading room with any manuscript materials "visibly in his possession."

Nevertheless, library police were concerned about what they regarded as a staff-condoned "breach of security" with respect to Mount.

The most serious security lapse, according to the statement, was the library's decision to give Mount his own, unsupervised "personal work space" in the administrative offices across the hall from the police-guarded reading room..

"There are several doorways that lead into the manuscripts stacks via the administrative offices," the statement said. "The Library of Congress does not maintain a police inspection post within the administrative offices . . . {and Mount} was therefore not subjected to any inspection by police personnel."

Bush said a door leading from Mount's former work space to the stacks is always locked and has an alarm.

"It would have been impossible for him to get into the stacks, and researchers are not allowed to go in there," she said.

Bush said Mount had special research privileges at the library, including his own work space, because he had donated all his research notes to the library from books he had written.

"We always try to be nice to our donors," she said.

Bush praised the library police, adding that no one is blaming them for the apparent theft of documents. She said the library has "blind spots" in the reading room, such as behind pillars, and that officials are considering installing cameras to monitor "problem areas."

Mount has said in an interview that he had no special access to library documents. He said he seldom needed to use the reading room because he was using materials from his own files, which the library allowed him to keep in his work space.