[Damocles]

Most mass murderers, for example kill to settle a grudge or avenge a perceived wrong, targeting victims who are relatives, colleagues or members of an ethnic group they hate, the experts said.

Ummm...they're all AMERICANS!! Hello. Why are they afraid to mention that possibility??

[Snowy]

Why are they afraid to mention that possibility??

Because then that would give the terrorists what they want. Further terrorizing the people will not help matters. Most sane people know that there is a good possiblility that the shooter or shooters are muslim terrorists.