It wasn't Mohammed who founded Islam.

[dyresand]

Sophronius, the patriarch of Jerusalem in 636-7 when the city was surrendered to the Arab army of Caliph Umar, has written on the siege and surrender and knows nothing about islam or muhammad. He refers to the saracens as godless pagans. Sophronius died in 638 or 9 which gives us a fairly stable date for his commentary.

Curiously, there had been an earlier revolt by local jews aided by the Persians against Heraclitus and the Byzantines in 614. A jewish state was reestablished until peace was declared between the Byzantines and Persians in 628. The jews suffered a massacre at the hands of the Byzantines in retaliation.

For this reason it is frequently implied that the jews were not all that unhappy to see the Arabs coming.

The Jews and muslims have been collaborators since Mohammed was a baby. Islam is pretty much Old Testament Judaism without the Jews. Most of their doctrines are identical.

So it makes no since for a Muslim radicals to be killing jews if they follow the same teachings its barbaric and unnecessary.