DALLAS — The F.B.I. is treating the assault on a suburban Fort Worth synagogue on Saturday as “an act of terrorism targeting the Jewish community,” Christopher A. Wray, the bureau’s director, stated on Thursday. “This was not some random occurrence,” Mr. Wray instructed viewers of a webinar hosted by the Anti-Defamation League. “It was intentional, it was symbolic and we’re not going to tolerate antisemitism in this country.” The bureau initially stated that the attacker, a British citizen named Malik Faisal Akram, was not pushed by antisemitism when he held 4 individuals on the synagogue hostage for 11 hours. At...