A Texas man linked to the worldwide hacking group Anonymous is facing federal charges for YouTube videos and Twitter postings in which he taunts the FBI and threatens to ruin one agent's life.

Barrett Brown was taken into federal custody in Dallas last month, but authorities wouldn't say why he was being detained until Thursday, when the U.S. attorney's office announced a three-count indictment against him.

The 31-year-old Brown is charged with Internet threats, conspiracy to make publically available restricted personal information of a government employee and retaliation against a federal law enforcement officer.

The indictment lists several tweets in which Brown talks about having a "plan to kill every government you meet" and taunts the FBI. It also quotes from a YouTube video entitled in part, "Why I'm Going to Destroy FBI Agent Robert Smith."

Brown uses several expletives in the video and complains that authorities are harassing his mother, who he says is innocent.

"So that's why Robert Smith's life is over," Brown said in the video. "But when I say his life is over, I don't say I'm going to go kill him. But I am going to ruin his life and look into his (expletive) kids."

Brown has previously been linked to the Anonymous movement of cyber-rebels and was often quoted in media reports about the shadowy movement.

The writer was the subject of a raid by the FBI in March, after the FBI and other law enforcement agencies swooped in on alleged members of the Lulz Security hacking collective. Lulz is an Anonymous offshoot that claimed responsibility for a series of eye-catching electronic attacks against Sony Corp., FBI affiliate groups and the U.S. Public Broadcasting Service.

Doug Morris, a federal public defender assigned to represent Brown, declined to comment.

An earlier attorney for Brown, Jay Leiderman, also declined comment Thursday, saying he needed a chance to review the indictment. Leiderman has said he believed some of the charges stemmed from a YouTube video in which Brown rails against law enforcement.