A man has been arrested in connection with the discovery of a 300-year-old ledger, bound in human skin, that was found in Leeds city centre.
Tests are being carried out to determine the book's origin
Written mainly in French, the macabre covering was said to be a regular sight during the 18th and 19th Centuries.
Accounts of murder trials were often bound in the killer's skin in a process known as anthropodermic bibliopegy.
The book was found in The Headrow and is thought to have been dropped after a burglary, police said.
A series of tests are being carried out on the ancient work to determine its origin.
Detectives said the book may have been stolen in West or North Yorkshire and appealed to anyone who may have owned it to contact them.