A Muslim convert from Brooklyn pleaded guilty Thursday in Alexandria, Va., to posting online threats against the creators of the South Park television show and others he deemed enemies of Islam.

In court papers filed Thursday with his guilty plea, Jesse Curtis Morton, 33, admitted that his now-defunct Revolution Muslim website served as an outlet for al-Qaida propaganda and that he used the site to post thinly veiled threats not only against South Park creators Matt Stone and Trey Parker but others he considered to be enemies of Islam.

Morton, who also uses the name Younus Abdullah Mohammad, worked closely with Zachary Adam Chesser, who was sentenced last year to 25 years in prison for the South Park threats and other crimes.

Morton left the U.S. and took a teaching job in Morocco days after Chesser's July 2010 arrest, fearing he, too, would be charged. He was arrested in Morocco in October and has been in custody since then, mostly in solitary confinement at the city jail in Alexandria.

Tried to join al-Shabab

Morton and Chesser's cases differ in significant ways, though. Chesser, in addition to threatening the South Park creators, also tried twice to travel to Somalia to join the jihadist group al-Shabab. On his second attempt he boarded an international flight with his infant child in tow, hoping his travel would appear less suspicious if he was accompanied by a baby.

The case against Morton rests solely on actions he took as founder and operator of Revolution Muslim. While the site was running, Morton took steps to portray its posts and commentary as solely informational or analytical.

For instance, when he posted the first issue of the al-Qaida magazine Inspire on his site in 2010, he posted a disclaimer saying it "should not be deemed that we are displaying any advice or support, material or otherwise, for any institution deemed illegal or terroristic by the U.S. government and its thought police."

The magazine included instructions on how to make a bomb and an explicit call from al-Qaida cleric Anwar al-Awlaki for the assassination of Seattle cartoonist Molly Nelson, who had proposed "Everybody Draw Muhammad Day" in response to the controversy over the 2010 South Park episode, which depicted the prophet Muhammad in a bear costume. Many Muslims consider drawings of Muhammad to be offensive, and Nelson was forced to go into hiding.

Morton and Chesser worked closely on crafting statements in response to the South Park controversy that they thought would be legally permissible but still convey a clear threat that would encourage others to take violent action against the show's creators.

Raised death of Theo Van Gogh

The statements "predicted" that Stone and Parker would meet the same fate as Theo Van Gogh, a Dutch filmmaker who was murdered in 2004 for making a movie that was perceived as insulting to Islam. Chesser had earlier posted a photo of Van Gogh's corpse along with the address of Comedy Central, where South Park airs, and a suggestion that readers "pay a visit" to Stone and Parker.

"He's acknowledged he broke the law, and it's just for him to face punishment," Morton's lawyer, James Hundley, said after Thursday's hearing. "He admitted crossing the line, though he was trying very hard not to."

But Neil MacBride, U.S. attorney for the Eastern District of Virginia, said Morton's whole intent in operating Revolution Muslim was to inspire people to engage in violent jihad.

"He pled guilty to operating Revolution Muslim with a clear desire to radicalize those who listened to and read what he posted," said MacBride, whose office prosecuted the case. "His purpose was to inspire others to engage in terrorism."

Following the South Park controversy, Morton and Chesser discussed the fact that "Revolution Muslim" had become the 68th most searched term on Google and looked for ways to capitalize on their exposure, according to an FBI affidavit.

The court documents include a long list of people convicted of radical activity who were regular readers of Revolution Muslim's materials.

Readers convicted of radical acts

They include Colleen LaRose, also known as "Jihad Jane," who was convicted last year in Philadelphia of terrorism-related offenses; Antonio B. Martinez, who was convicted last month in Baltimore of plotting to bomb a military recruiting station; Jose Pimental, who sent an email to Revolution Muslim saying he was a "big fan" and was later charged in connection with a plot to kill U.S. military members returning from Iraq and Afghanistan; and Samir Khan, a U.S. citizen who became an al-Qaida propagandist and was killed in the airstrike last year that also killed al-Awlaki.

"In some ways the 'South Park' threats were probably the least significant of the things that were happening" with Revolution Muslim, said Assistant U.S. Attorney Gordon Kromberg, who prosecuted the case.

A call to Comedy Central was not immediately returned Thursday.