The Manhattan District Attorney's office obtained the subpoena after Twitter refused an emergency information request from the police department, the New York Post reported Tuesday.
Police said the threat involved the Longacre Theatre in Midtown where Mike Tyson's one-man show, "Undisputed Truth," is playing.
"Gosh I'm still making this hit list damn I wanna kill a lot of people," the poster tweeted. "I'm serious people are gonna die like Aurora."
He referred to last month's massacre in an Aurora, Colo. movie theater where 12 people were killed and another 58 wounded during a midnight performance of "The Dark Knight Rises."
"We'll cover the theater until we find this guy," said NYPD spokesman Paul Browne.
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