Krupp said the ultimate target of the subpoena is a blogger who calls himself Guido Fawkes, and who goes by the Twitter handle @P0isAn0N . The blogger’s true identity was not immediately known. Krupp said he could not say why Fawkes was targeted by authorities, because court documents were sealed.

Peter Krupp, an attorney from Lurie and Krupp LLC, who is working on behalf of the ACLU, said the ACLU has moved to have the subpoena, sent to Twitter, quashed on First Amendment grounds. A hearing has been continued to today in Suffolk Superior Court.

The American Civil Liberties Union of Massachusetts is fighting on behalf of a blogger with apparent Occupy Boston ties who has been subjected to a subpoena that authorities filed through a social media site.


The use of Twitter information in investigations is a rare, but not unheard-of tool for law enforcement. Last year, federal authorities sought information on Twitter related to the WikiLeaks organization, and a federal judge upheld the request.

But Twitter has become known for opposing such requests and even alerting users of law-enforcement subpoenas.

A week ago, Fawkes tweeted a link to the subpoena that Boston police and the Suffolk district attorney’s officehad sent to Twitter in California requesting Internet protocol addresses on his Twitter account, as well as details on the @OccupyBoston Twitter account and for Twitter users who used the hashtags #BostonPD and #d0xcak3.

Hashtags are used to mark keywords or topics in a tweet, or comment, posted on Twitter.

The subpoena, dated Dec. 14, says the request is “pursuant to an official criminal investigation.’’

Fawkes sent a tweet Friday asking, “@Boston-Police why are you trying to subpoena my account? For free speech? #umad?’’

Jake Wark, a spokesman for the district attorney’s office, said he could not confirm, deny, or discuss any investigation in which no criminal charges have been filed.


Twitter notified Fawkes that his information was being subpoenaed and gave him an opportunity to oppose the request, according to Fawkes’s Internet postings.

The social media site says its policy is to protect users’ personal information.

Internet bloggers have speculated that the investigation is related to the police raid on Dec. 10 that evicted Occupy Boston demonstrators. The subpoena sent to Twitter requested information for the period from Dec. 8 through Dec. 13.

Speculation has also centered on a tweet that Fawkes sent in October linking to a website that listed the personal information of ranking Boston police officers. Anonymous hackers apparently obtained the information from a members-only police union site and posted them on an open site.

Fawkes had used the hashtag #d0xcak3 when tweeting the link, according to Internet blog sites.

The nature of the subpoena was quickly denounced by civil rights groups and Internet bloggers, who asserted that the subpoena was far-ranging and seemed to request the information of anyone who used the hashtags.

Fawkes tweeted a link to his comment to law enforcement authorities earlier this week, saying, “Your subpoenas will not shake me.

“You cannot arrest an idea. You cannot subpoena a hashtag,’’ he said.

Milton J. Valencia can be reached at mvalencia@globe.com. Follow him on Twitter @miltonvalencia.