Police are increasingly turning to Oyster travel cards to track
criminals' movements, according to new figures.

The smartcards, used by five million Londoners, record details
of each bus, Tube or train journey made by the holder over the
previous eight weeks.

The Metropolitan Police said it was a "straightforward
investigative tool" used on a case-by-case basis.

http://news.bbc.co.uk/1/hi/england/london/4800490.stm
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Roland Perry