"join to" -- headline problem

[Joel S. Berson]

"FBI joins police to ID threats."  [Headline, Boston Globe.]

For a moment, I thought this meant "FBI associates [local] police 
with ID threats", something sadly all too conceivable these 
days.  (And -- are these threats to personal ID protection and privacy?)

Actually, it's  the FBI cooperating with police in identifying 
perpetrators of threats -- made anonymously to several high schools 
in Massachusetts the past two weeks, forcing them to close abruptly.

Joel

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