Aroboles,
To me is clear the reason why John doesn't mention the destruction of the Second Temple in Jerusalem: Because all of his writings were produced BEFORE the 66-70 CE crisis. See further details on my article "Dating Revelation - Solely With Internal Evidence from the New testament" I'm actually well persuaded that he started to receive the visions of Revelation by 41 CE. If this is indeed true, then it explains A LOT about the other writings of Paul and Peter and its the simplest explanation for the lack of any reference to the destruction of Jerusalem and its temple in 70 CE.
As for Eusebius, there seems to be no other source that I'm aware of. He also spoke based on earlier sources, but it's what we've got. In any case, I think that the persecutions from the Jewish leaders and Nerus did more to make the Hebrew Christians disperse from Jerusalem into other areas of the Roman Empire, than actually the events during the 66-70 crisis. Tradition has it (but on what reliable source?) that the last members of the congregation in Jerusalem left the city towards Pella after celebrating Pentecost in the city in 69 CE. I assume that, by then, none of the original twelve apostles was part of that remnant.
Eden