Last year Calvert admitted possessing an offensive weapon, malicious damage and attempting to escape custody but denied affray.

BBC: Michael Calvert

David Saunders, head of conservation and scientific research at the museum, said there had been very little malicious damage.

BBC: London

Viruses -- the first generation of the computer culprits -- are used for the computer equivalent of vandalism, as the malicious programs replicate, spread and damage computers.

CNN: Twitter message could be cyber criminal at work