>My understanding is that they were extremely well concealed
Source? I'm not sure how you can concealed any meaningful amount of PCB/explosive in a pager/radio, unless you're hoping that your target never opens the plastic casing, or doesn't know what the internals are supposed to look like.
Source? I'm not sure how you can concealed any meaningful amount of PCB/explosive in a pager/radio, unless you're hoping that your target never opens the plastic casing, or doesn't know what the internals are supposed to look like.