ROME, Nov. 14 -- A wave of hoax bomb threats targeting schools, airlines and media organizations has recently swept across Europe, disrupting public services and heightening security concerns.

As similar threats spill across national borders via hijacked email accounts and anonymous networks, European authorities face mounting pressure in identifying those responsible.

Though it remains unclear who is behind the threats hitting France, Spain, and other nations, European officials call them a coordinated effort to sow continent-wide confusion.

Regardless of who is responsible, how exactly are hoax bomb threats causing widespread disruption across Europe?

ORIGIN UNKNOWN

In Italy, around 6,300 schools received bomb threat emails on Wedn...