(CNN) -- A radical Islamic website says despite a provocative post -- warning the creators of "South Park" that they risk violent retribution for depicting the Prophet Mohammed in a bear suit -- the site is calling simply for protest, not violence.

Revolutionmuslim.com, based in New York, was the subject of a CNN investigation last year for its radical rhetoric supporting "jihad" against the West and praising al Qaeda leader Osama bin Laden. Its organizers insist they act within the law and seek to protect Islam.

On Sunday, Revolutionmuslim.com posted an entry that included a warning to "South Park" creators Trey Parker and Matt Stone that they risk violent retribution -- after the 200th episode of the cartoon series last week included a satirical discussion about whether an image of the prophet could be shown. In the end, he was portrayed disguised in a bear suit.

"We have to warn Matt and Trey that what they are doing is stupid," the posting on Revolutionmuslim.com says, "and they will probably wind up like Theo Van Gogh for airing this show. This is not a threat, but a warning of the reality of what will likely happen to them."

Read CNN blog about RevolutionMuslim.com's post

Dutch filmmaker Theo van Gogh was stabbed to death on a street in Amsterdam, Netherlands, by an Islamic extremist in 2004. He became the target of radical Muslims after releasing a short film about oppression of Islamic women in Europe.

Abu Talhah al Amrikee, the author of the post, told CNN it was meant to show those offended by the depiction of Mohammed how they can voice their opposition, including by sending letters to the South Park's creators. The group is also considering demonstrations.

The posting provides the addresses of Comedy Central, which airs "South Park," and the show's production company. A spokesman for Comedy Central said they had no comment on the posting.

Over still photographs of Parker, Stone, van Gogh and others, the website runs audio of a sermon by the radical U.S.-born preacher Anwar al-Awlaki, who is now in hiding in Yemen. The sermon, recorded some time ago, talks about assassinating those who have "defamed" the Prophet Mohammed -- citing one religious authority as saying "Harming Allah and his messenger is a reason to encourage Muslims to kill whoever does that."

U.S. officials say al-Awlaki is on a list of al Qaeda leaders targeted for capture or assassination.

Al Amrikee said the purpose of including the al-Awlaki sermon in his posting was to remind Muslims that insulting the prophet is a severe offense for which the punishment in Islam is death.

The clip ends with a warning on a graphic directed at Parker and Stone, saying "The Dust Will Never Settle Down."

It's a word game, federal officials tells CNN, that allows the group to post support of terrorists, like the alleged Fort Hood, Texas, shooter, on its website. The website is protected under free speech laws of the United States.

"Certainly the comment on this website is very ugly, but it is certainly not specific enough to get anyone arrested," CNN legal analyst Jeffrey Toobin said.

Last year, CNN asked one of the founders of the radical group in New York to explain its philosophy.

Younes Mohammed chose his words carefully, telling CNN he saw nothing wrong with Americans dying in the September 11, 2001, terrorist attack.

"I don't think it was wrong," Mohammed said. "I think it was justified."

He added, however, he does not encourage any violence on U.S. soil.

And Mohammed said he also doesn't see anything wrong with his messages -- he dislikes the United States and he yearns for a Muslim world.

"We're commanded to terrorize the disbelievers and this is a religion ...," Mohammed said. "The Quran says very clearly, in the Arabic language ... terrorize them. It's a command from Allah."

"I define terrorism as making them fearful so that they think twice before they go rape your mother or kill your brother or go onto your land and try to steal your resources," he added.