(Martin FamilyAP Photo; Orange County Jail via Miami Herald/AP Photo)

ABC News' Marisa Taylor reports:

The tensions over the slaying of Florida teenager Trayvon Martin has spawned threatening online comments with one Twitter user going so far as to create the hashtag @KillZimmerman, an example of postings that authorities have apparently not acted on.

A Twitter account called @KillZimmerman was created March 24 in which the user posted a photo of  Zimmerman in the cross hairs of a gun. A quote on the account user's Twitter page reads: RiP "This Page Is 4 Da Ppl Who Believe Zimmerman Should Be Shot Dead In The Street The Same Way TRAYVON Was. No Justice No Peace #KillZimmerman."

The owner of the @KillZimmerman account wrote 454 tweets from March 24 to March 28 and, as of Friday afternoon, it had 463 followers. ABC reached out to the owner of @KillZimmerman via a tweet, but he or she did not respond to a request for comment. Despite outrage across the blogosphere, the account has not been taken down or suspended.

Both Sanford police and the state attorney declined to comment on the social media postings.

Twitter has also stayed out of the fray.  "We don't comment on individual accounts as a policy, for privacy reasons," company spokeswoman Rachael Horwitz said. According to Twitter's rules, the site "[doesn't] actively monitor user's content and will not censor user content."

But the rules also say that Twitter users "may not publish or post direct, specific threats of violence against others." Specific threats of violence by a Twitter user are considered a violation of the site's terms of service, Horwitz said.

Twitter maintains a page where individuals or their authorized representatives who have received specific threats of violence can report the threats to Twitter by providing links to the tweets that specifically threaten violence.

Twitter said that it responds quickly to such reports. In the case of @KillZimmerman, the account owner's first tweet Mar. 24 said: " #TRAYVONMARTIN No Justice No Peace!!!!!!!!!! #KILLZIMMERMAN #KILLZIMMERMAN #KILLZIMMERMAN." Whether the tweet constitutes a specific threat of violence could be interpreted in more than one way. The user doesn't specify how Zimmerman should be killed, but it does specify that he indeed should be killed.

Days later, on Mar. 28, @KillZimmerman went on to tweet: "They act like they wanna charge me but I'm not the one who shot an unarmed kid #zimmerman is so judge him." Dismayed Twitter user @S_Anton_II responded: " @KillZimmerman Well, you're acomplishing [sic] one thing: highlighting how stupid, ignorant and primitive some people are." On Mar. 28, @KillZimmerman also wrote: "So coz I made this account they automatically think I'm black smfh. Racist bastards!!!!" (SMFH refers to the phrase "shaking my f**king head," according to UrbanDictionary.com.)

Facebook pages advocating the killing of Zimmerman have also been created. A Facebook page called "Kill Zimmerman," which features a picture of a smiling Martin holding his baby brother, has 39 "likes."

Another page is titled: "my crib wondering whos going to kill george zimmerman.. RIP TRAYVON," but only 12 users have "liked" it.

And eponymous director Spike Lee also made headlines when he tweeted the incorrect home address of Zimmerman, which turned out to be the address of David McClain, 72, and his wife Elaine McClain, 70. The couple has said they are now living in a hotel and said they are concerned for their safety. Spike Lee reportedly settled with the couple, and called them to apologize for putting them in danger, according to the Tampa Bay Times.

The terms of the settlement were not disclosed. As for whether the Sanford Police Department is aware of the @KillZimmerman Twitter account or has received any death threats against Zimmerman, a spokesman who identified herself only as "Lucy" told ABC News that the department is "not authorized to comment on any aspect of this case."

She referred ABC News to the State Attorney's Office for the Fourth Judicial Circuit of Florida, but State Attorney Angela Corey did not immediately respond to an email requesting comment. In a statement,  however, she said, "We appreciate both your interest in the case and the public's desire to know more details. But in order to protect the integrity of the case, there will be no further comment at this time.

"For the sake of all involved," she said, "please allow us to do our jobs within the bounds of Florida law."