Police patrols aided with sniffer dogs are seen at Beijing's metro stations on March 30, 2010. [Xinhua]
![Police patrols aided with sniffer dogs are seen at Beijing's metro stations on March 30, 2010. [Xinhua]](../../attachement/jpg/site1007/20100331/0019b93bd68d0d1cfc2929.jpg "Police patrols aided with sniffer dogs are seen at Beijing's metro stations on March 30, 2010. [Xinhua]")
