Fairfax County Library officials have found antiabortion messages, including footage of fetuses, added to the end of videotapes borrowed from their collections.

The graphic messages on four or five tapes -- including tapes meant for small children -- have been discovered in two libraries since June, said Library System Director Edwin S. Clay.

Library officials learned of the messages in June when a patron returned a video to the Tysons-Pimmit Regional Library and complained that an antiabortion film had been added after the credits at the end of the tape.

Staff members found several other altered tapes at Tysons-Pimmit, and another patron discovered antiabortion messages on a tape at George Mason Regional Library, Clay said.

Library staff members have been asked to check for tampering on any tapes they use, but the 19,000- tape collection is too big to search, Clay said. Library officials have erased all the messages that have been found, he said.

Tapes containing what appear to be highlights of an antiabortion meeting -- including graphic descriptions of how abortions are performed -- have been turning up at Tysons-Pimmit since June, library officials said.

The problem was noticed at George Mason in early August, said Regional Information Librarian Liz Promen.

There, a patron found the messages at the end of "The Elephant's Child," a Rabbit Ears children's video based on a Rudyard Kipling story, Promen said.

Promen, who viewed part of the message, said she saw written biblical verses related to childbirth and children and descriptions of child development accompanied by pictures of fetuses.

"It was not material appropriate for young children," she said.

Library officials said they do not know when or how the messages were added to the tapes, but current technology makes copying scenes from one videotape to another fairly easy. Officials said they don't know if the messages had been put on the tapes before they received them.

The messages may have gone undetected for some time because many borrowers stop the tapes during the credits and never reach the portion of the tape where the antiabortion messages are located, library officials said.

The tamperers could face fines for defacing county property, but library officials say they have little opportunity to catch the perpetrators. As a matter of policy, the library system does not keep track of who has checked out a book or tape after the item has been returned.

"We don't want to maintain a record of what you have checked out," Clay said. "It's nobody's business but yours."