A member of the grand jury that declined to indict the Ferguson police officer who fatally shot 18-year-old Michael Brown asked a federal court Monday to remove a lifetime gag order preventing jurors from discussing the case.

The American Civil Liberties Union filed the lawsuit on behalf of an unnamed juror who wants to speak about the investigation but would be in violation of Missouri law by doing so.

The lawsuit also questions St. Louis County prosecutor Bob McCulloch's characterization that "all grand jurors believed that there was no support for any charges."

The suit was filed against McCulloch, who oversaw the investigation, because his office would be responsible for bringing charges against the juror, according to the ACLU. McCulloch's spokesman, Ed Magee, said his office had not seen the lawsuit and declined immediate comment.

"Right now there are only 12 people who can't talk about the evidence out there," ACLU attorney Tony Rothert said. "The people who know the most — those 12 people are sworn to secrecy. What (the grand juror) wants is to be able to be part of the conversation."

The suit does not seek to allow grand jurors in all Missouri cases to be free to discuss proceedings. But it argues that the Ferguson case was unique, and that allowing the juror to speak would benefit the national debate about race and police tactics that was sparked by the shooting.