The Northern Territory's most senior cop says police are relying on the community to help combat the rapidly increasing threat of violent extremism and radicalisation through online platforms.Two NT teenagers have been charged with terrorism related offences in the last six months, including a 15-year-old arrested last week for allegedly possessing violent extremist material.Investigators alleged the teenager, who cannot be identified for legal reasons, collected documents "likely to facilitate a terrorist act" as well as schematics for 3D-printed firearms.Police sources later told the ABC the teenager had allegedly expressed support for both the 1999 Columbine High School massacre and white...