A writer linked to online hacking collective Anonymous has been sentenced to prison for threatening an FBI agent and two other federal counts in a closely watched case.

Barrett Lancaster Brown was sentenced to five years in prison Thursday in federal court in Dallas. The 33-year-old has already been jailed for more than two years.

Brown is often quoted on the workings of Anonymous, the worldwide hacking collective.

He came under federal investigation for posting a link to data stolen from the Austin-based defense contractor Stratfor. He later admitted to posting threats against an FBI agent, obstructing a search warrant and being an accessory to an unauthorized access of a protected computer.

Brown's case has been closely watched by free-speech advocates who have criticized his prosecution.