NEW YORK: The New York Police Department has used a subpoena to force Twitter to disclose information about the source of a tweet saying people were going to die at the Broadway theater staging a one-man show by former heavyweight champ Mike Tyson, the department said Tuesday. 

The NYPD sought the subpoena after Twitter refused to cooperate in a probe of ominous posts that referenced the shooting deaths last month of 12 people last month at a showing of ''The Dark Knight Rises'' at an Aurora, Colorado, movie theater, said NYPD spokesman Paul Browne.

Police received new information from Twitter on Tuesday ''that we're using as part of our ongoing investigation,'' the spokesman said. He offered no further details.

A Twitter spokeswoman declined to comment Tuesday.

Police say the tweets appeared aimed at the audience for ''Mike Tyson: Undisputed Truth,'' the solo show directed by Spike Lee at the Longacre Theater in midtown Manhattan.

''This s--- ain't no joke yo I'm serious people are gonna die just like in aurora,'' police said one tweet read. Another from the same account warned, ''I'm in Florida rite now, but it'll happen i promise I'm just finishing up my hit list.''

Before complying with the subpoena, Twitter had told the NYPD in an email, ''We appreciate the timeliness and sensitivity of this matter, and have reviewed the reported Twitter account.

While we do invoke emergency disclosure procedures when it appears that a threat is present, specific and immediate, this does not appear to fall under those strict parameter as per our policies.''

Browne said the NYPD has beefed up security at Longacre as a precaution.