On 11 September a 33-year-old man was detained in the Strabane area for a mortar bomb found pointed at the police station. The improvised explosive device was positioned close to a family home, and the incident has been blamed on a dissident republican group, the New IRA. Within 48 hours of the bomb being discovered officers moved into the Creggan estate en masse, quickly locating a command-wire activated device built to kill a passing police patrol. Senior officers clearly knew what they were looking for and where it was placed - precise information that must have come from what they describe as a Covert Human Intelligence Source (CHIS). Many believe the New IRA, like all paramilitary gangs past and present, is filled to the brim with such informers.