[RayChuang88]

The idea of a hidden bomb is not as far-fetched as some claim. There are a lot of "quiet dissidents" in the Iranian government that hate dealing with Hamas, a Sunni Islam organization (Iranian Muslims follow Shi'a Islam), and the death of that Hamas leader is quietly welcomed by those dissident elements.

[ChronicMA]

If the bomb was planted by Iranian security people, even though funded by Israel, the case for punishing Israel falls apart.

It was an inside job.