(CNN) -- A New York man charged with posting online threats against creators of the television show "South Park" is expected to plead guilty Thursday in a Virginia federal court, a senior U.S. counter-terrorism official said. Jesse Curtis Morton was the co-founder of Revolution Muslim, a radical group based in New York City that is supportive of al Qaeda's worldview. The former Brooklyn resident, also known as Younus Abdullah Mohammad, was taken into U.S. custody in Morocco on October 28, according to court documents. Morton left the United States in summer of 2010 because he feared arrest after two associates from New Jersey were charged with terrorism offenses in June of that year, according to the official. Investigations had revealed that Revolution Muslim was the "top catalyst for radicalization for violence in the United States" over the last several years, according to the official. Morton had a multitude of connections to individuals charged or convicted in U.S terrorism cases, the official said. They included Zachary Adam Chesser, now 21, who last year admitted to posting online threats and attempting to provide material support to Al-Shabaab, a designated foreign terrorist organization. He was sentenced to 25 years in prison. Chesser, a Muslim convert like Morton, communicated threats against the writers of "South Park" for an episode that depicted the Prophet Mohammed in a bear suit. Chesser posted online messages that included the writers' residence and urged online readers to "pay them a visit," the Department of Justice said. In an affidavit accompanying the complaint against Morton, FBI special agent Paula R. Menges said Morton worked with Chesser on a "clarification statement" after the latter's postings. The pair made website postings that were threats -- despite their claims otherwise, Menges said. Morton's links with extremists included Samir Khan, the editor of al Qaeda in the Arabian Peninsula's English-language NFL jerseys supply inspired magazine. Khan was killed last September along with Anwar Awlaki in a U.S. drone strike. Khan knew Morton from his days living in New York and invited him to contribute to a radical blog he was producing in North Carolina called "Jihad Recollections," before traveling to join AQAP in Yemen in October 2009, according to the official. Khan told Morton of his plans to travel to Yemen, according to the senior U.S. official. The official was unaware of any communications between the two after Khan left the United States. Rezwan Ferdaus, a U.S. citizen from Ashland, Massachusetts, who was charged with planning to use model aircraft filled with C-4 plastic explosives in an attack against targets in Washington in September was in touch with Morton as he prepared his operation, according to the official. Ferdaus asked Morton about the Islamic justification of suicide bombings. Morton cheap NFL jerseys replied that what was key was the intention behind them and that they were an enormous benefit in a war of attrition, according to the official. Morton later invited Ferdaus to speak in more detail in an online conference call he was holding on the website Paltalk. In the e-mails, Ferdaus did not reveal his specific plan, according to the official. Ferdaus has pleaded not guilty to the plot. Jose Pimentel, a Bronx resident who in November was arrested and charged with plotting to detonate pipe bombs in New York City after allegedly beginning to build an explosive device was in touch with Morton via e-mail before he was arrested, according to the official. Pimentel wrote that he was big fan of the Revolution Muslim website and "Islam Policy," another website run by Morton, and asked Morton about whether he could trust a particular individual, according to the official. Pimentel has pleaded not guilty to the plot. Morton's group was connected online to several others who have admitted or been charged in connection with terrorist offenses. Colleen LaRose, an American woman who pleaded guilty last year to conspiring to assassinate a Swedish cartoonist in 2009, was a subscriber to Revolution Muslim's website. Antonio Martinez, a Hispanic convert to Islam who pleaded guilty to a plot to blow up a Maryland military recruiting station in 2010, also visited the website - but was not in direct touch with its founders, according to the official. Abdel Hameed Shehadeh, arrested in Hawaii in October 2010 and charged with making false statements in a matter involving international terrorism, attended Revolution Muslim meetings and made his website a feeder for Revolution Muslim's, according to the official. Shehadeh, who authorities alleged attempted to travel to fight jihad overseas, pleaded not guilty. Morton's associates in New Jersey were Mohammed Alessa and Carlos Almonte who last year pleaded guilty to conspiring to murder individuals on behalf of a terrorist group in Somalia. Alessa and Almonte were arrested as they tried to board international flights at a New York airport on June 5, 2010. A few days later, Morton arranged for tickets to fly to Morocco. Morton also had a web of international connections, according to officials. He was in touch with Mohammed Chowdhury, the ringleader of a plot to blow up the London stock exchange and other London targets in December 2010, who pleaded guilty last week. When Morton moved to Morocco, he asked Chowdhury to take over the running of the Revolution Muslim website, according to the official. Chowdhury was part of a group of radical extremists linked to the British pro-al Qaeda group al Muhajiroun, whose former members have been implicated in several U.K. terrorist plots. Morton's group Revolution Muslim was nfl headset a spinoff of the American wing of Al Muhajiroun. The British group is still active in the U.K., operating under different names. According to the U.S. official, Morton was also in touch with Bilal Ahmad, another member of the same British extremist circle. Ahmad pleaded guilty to soliciting murder after posting a death threat in November 2010 on the Revolution Muslim website against British parliamentarians who had supported the Iraq war. In a CNN interview in 2009, Morton defended the September 11, 2001, terrorist attacks and argued that further attacks on Americans were justified. However, he said he did not encourage violence on U.S. soil. CNN's Drew Griffin contributed to this report.
