Thefts at the British Library

An article from the Guardian in the UK from November 21, 2008, describes the theft of single leaves from rare printed works in a number of Libraries in the UK, including the British Library and the Bodleian.
According to the article

'Using electronic records, they found all the British Library members who had taken out the book and then examined other works these people had had contact with. They discovered that other works detailing the same periods in history and covering European engagement to the area from modern-day Syria to Bangladesh were also damaged.'

Without the ability to electronically request, circulate and examine transaction data on our collections how easily could we follow the trail of a suspected thief?