Stockholm University Library has locked away five rare books in a bomb-proof vault after they were recovered from a thief who died when his apartment blew up.
The five scientific texts from the 16th and 17th century were among 11 books worth more than 1 million Kronor (£78,000) reported missing after an audit following thefts from the National Library and Uppsala University.
Access to the books in the nuclear bomb-proof storage room will be limited to key staff in future. Even university researchers are barred from admittance to inspect the books. It is not known whether they will be permanently denied access.
Police linked the stolen books to a man who died in an explosion two weeks before Christmas. An autopsy revealed that death was caused by carbon dioxide poisoning. Police believe he may have committed suicide.
Prior to his death, the man, previously employed at the National Library, was suspected of stealing rare books from the National and Stockholm University libraries.
Three texts from the library's rare books collection were found in his possession.
Two of these books, according to Sweden's daily newspaper Dagens Nyheter , were believed to have had their catalogue numbers removed. After the man's death, police shifted their investigation to retrieving the stolen books and investigating claims that the man had had one or more accomplices.
Four of the books were subsequently traced to a German auction house, where it was discovered the university stamp had been removed.
The five returned books were said to be in good condition despite minor damage connected with the attempt to remove the stamp.