A former spokesman for Anonymous was arrested late Wednesday, according to the hacker group and the Dallas County Sheriff’s Office, just hours after posting an online video in which he threatened an FBI agent.

Barrett Brown was arrested shortly before 11 p.m. and turned over to FBI custody, according to Carmen Castro, a spokeswoman for the Dallas County Sheriff’s Office. Castro could not say what he had been charged with. Brown's attorney, Jay Leiderman, told Wired.com his client was charged with making threats to a federal agent.

Katherine Chaumont, a spokeswoman for the Dallas office of the FBI, declined to comment.

Federal authorities have arrested several alleged members of Anonymous over the past year in an effort to disrupt the hacker group, which has taken credit for a series of high-profile cyber attacks.

In March, Brown’s home was raided by the FBI, which confiscated his laptop, according to Gawker.

His arrest Wednesday came just hours after he posted a YouTube video in which he appeared to threaten an FBI agent for allegedly harassing his mother.

Brown was one of the few public faces of Anonymous, a shadowy group that prides itself on not having central leadership. He has reportedly co-authored a book, which has yet to be published, about his experience working for the hacker collective.

On Thursday, Anonymous released a statement on the file-sharing site Pastebin detailing what it claimed were credit card numbers, addresses and phone numbers of 13 federal government employees. On Twitter, the hacker group said the release of the information was in retaliation for Brown's arrest, calling him “our controversial hated/loved friend.”

In 2010, Brown wrote a column for the Huffington Post, calling Anonymous “among the most important and under-reported social developments to have occurred in decades.”