But interception of post is still an available option for law enforcement and intelligence agencies , in certain circumstances .
As more people use faxes and e-mail the significance of surveilling the postal system is decreasing , in favor of Internet and telephone surveillance .
Interception of post is still an available option for law enforcement and intelligence agencies , in certain circumstances .
As more people use faxes and e-mail the significance of surveilling the postal system is decreasing , in favor of Internet and telephone surveillance .