[Campion]

I found it. He talks about the Jews being driven out of the region around Babylon, and moving to Seleucia. Once in Seleucia [Antiquities, Book 18, chapter 9, paragraph 9]:

Accordingly, they [Greeks and Syrians in Seleucia] fell upon them [the Jews], and slew about fifty thousand of them; nay, the Jews were all destroyed, excepting a few who escaped, either by the compassion which their friends or neighbors afforded them, in order to let them fly away. These retired to Ctesiphon, a Grecian city ...

It sounds like the Jewish population of the area around Babylon was driven out, and then mostly slaughtered.

[Uncle Chip]

I found it. He talks about the Jews being driven out of the region around Babylon, and moving to Seleucia. Once in Seleucia [Antiquities, Book 18, chapter 9, paragraph 9]: Accordingly, they [Greeks and Syrians in Seleucia] fell upon them [the Jews], and slew about fifty thousand of them; nay, the Jews were all destroyed, excepting a few who escaped, either by the compassion which their friends or neighbors afforded them, in order to let them fly away. These retired to Ctesiphon, a Grecian city ...

It sounds like the Jewish population of the area around Babylon was driven out, and then mostly slaughtered.

That is not what it says in the quote above. It says that the "50,000 Jews" who the Greeks fell upon were destroyed except a few of the 50,000.

This would have been northwestern Mesopotamia, an area outside of the Parthian Empire. Babylon and most of Babylonia was in the Parthian Empire. And let's see: 1,000,000 Jews minus 50,000 leaves 950,000 Jews in Babylonia around Babylon, a great mission field for the Apostle Peter, who may have read some of Josephus's writings before going to Babylon.