[ryuu]

Where would Palestinian factions get polonium from? I feel this to be an unlikely scenario.

[dodyg]

The most obvious ones were Pakistan, Iran and North Korea. You can find possible links between these countries to the Palestinians (especially via Syria and Hezbollah).

[ryuu]

This is a more far fetched scenario given that their immediate neighbor happens to have reactors.

I am not saying he was poisoned or not (I do not know). I am just going by Occam's Razor, here.