Federal prosecutors are alleging that a Hell’s Angels member threatened a witness — through a Facebook page “poke.”

The allegations, which run counter to the motorcycle club’s “tough-guy” image, were challenged this morning by a federal judge. Beforehand, however, the courtroom became an open forum in which lawyers, a probation officer, a court reporter, and, yes, even a newspaper reporter were asked by the judge for insight into how Facebook privacy settings work. (Only a few — newspaper reporter excluded — could provide answers.)

Today, a federal prosecutor asked that bail be revoked for Richard “Eric” Riedman, who authorities allege is a member of the Hell’s Angels. Riedman is awaiting trial on allegations that he and others stole scrap metal from a CSX railroad yard. An earlier trial on the charges ended up with a hung jury.

Riedman also was recently charged in connection with an alleged baseball bat beating by an Angel’s member of a man in a Lyell Avenue bar. Federal authorities allege that Riedman and others help set up and cover up the crime in the 2006 beating. Riedman faces a bail hearing in that case tomorrow.

At today’s hearing, Assistant U.S. Attorney Brett Harvey contended that Riedman’s bail should be revoked in the scrap metal case because he allegedly “poked” a cooperating witness — Christopher Monfort — through Facebook. That “poke” — a largely meaningless Facebook communication method — came from the Facebook page of “Erock Shock,” which turned out to be Riedman’s.

On the page were earlier postings by Riedman stating “Retribution,” a video of Riedman playing a guitar, and a photo of a tattoo stating “WAR,” which prosecutors say is a Rochester chapter Hell’s Angel acronym for “We’re Always Right.”

In court today, Riedman’s attorney, Michael Tallon, said “Retribution” is a name of both a band that Riedman likes and a song they perform.

Authorities allege that Riedman was ordered not to have contact with Monfort, who testified for almost nine days in the earlier scrap metal trial. They also allege that the Facebook “poke” could be the basis of a criminal charge of tampering with a witness.

U.S. District Judge Charles Siragusa questioned today why prosecutors didn’t criminally charge Riedman if they believed they had sufficient proof he had tried to intimidate a witness. Harvey said prosecutors might not have enough evidence to prove guilt because Riedman’s computer is now being monitored after being seized.

Harvey acknowledged, “This isn’t a straightforward … threat.”

Siragusa refused to detain Riedman, who is jailed for now on the other charge, and asked prosecutors to send more information after the computer is analyzed.