Authorities are questioning why none of the bombs went off.

The FBI called them “potentially destructive devices” in the press release. So either the bomb maker was good enough to ensure none would go off and never intended them to explode -- or they were poorly constructed.

However, the presence of what is believed to be pyrotechnic powder is one reason why authorities consider them to be potentially destructive.

Though it appears they were handled through the postal system -- jostled and moved -- without any explosion, outside experts who have viewed photos of the devices have pointed to the lack of a triggering mechanism, suggesting they perhaps were never meant to explode.

The construct includes very common components, making it more difficult to get clues from the signature of the bomb. But the components could still provide clues -- like the clock and the tape used.