An article by Graham Fraser reports that workmen found bones in the Chapel during conservation work:
The bones, which were found on February 19, have now been removed from the site to be examined by archaeologists to discover their age, type and if they are human or animal. They were discovered under a slab while a new heating system was being installed inside the chapel. There is no record of a burial site in this particular area of the chapel.
The local police are not treating the discovery as a crime, which implies the bones are very old. Rosslyn Chapel authorities have declined to comment. The crypt has been used for the burial of descendants of William St. Clair who built the chapel, and the Sinclair family, but the new discovery is not in an area historically used for interment of bodies.
The famous 15th century chapel is associated by various authors with early Scottish Freemasonry, the Knights Templar, and wide range of pseudo-historical claims, along with being the location of the climax of Dan Brown's The Da Vinci Code. It is undergoing a US$20 million renovation and restoration project.