"Xenophobia" is a specific fear, namely, the fear of foreign or strange people or things. Your sentence thus means:
There was also the fear of foreigners that the foreigners would kill people.
And that doesn't really make sense.
If you want to indicate that the fears were unfounded or based on hysteria, I'd suggest using an adjective like "irrational":
There was also the irrational fear that...
- For Teachers