Martin Eastburn fired this volley in
:

cell phones in the Boston bombing...

I don't know if you recognize any of the common parts shown in the photos
of the debris, but there we

1) parts of a standard 7.2V NiCd 'hobby' style battery pack for models
(cars and planes)
2) parts of an electronic speed controller for RC cars or planes...
looked like a Great Planes or Novak component (in-line style) ESC.
3 parts of a Novak RC radio receiver for cars or planes (orange case,
very recognizable)

I'll let you guess from that whether or not cell phones were used as the
firing box. I'm guessin' your guessin' won't be swayed by this.

(I'm in an explosives-related biz, so ways to ignite things are
reasonably familiar to me)

Lloyd