behind us and, you know, something was telling me, something is not right. i just kind of kept looking back there. >> reporter: now authorities have not identified the gunman. we know several agencies are involved, local law enforcement, the atf, the fbi. they know he was a transient person with roots to this community, but he did not necessarily live here. he's had multiple arrests, different run-ins with law enforcement but not on any known watch lists. >> the quick reaction of the armed members of the congregation you see on the tape, remarkable. thanks very much. now for more on what we're learning about the attack in new york, where five people were stabbed during a hanukkah celebration in a rabbi's home, cnn's brita brin gingras is in new york. they're still trying to determine a motive here. is that in question?