NBC has launched an internal probe after running an edited version of the 911 call from George Zimmerman -- the man who shot and killed Trayvon Martin -- that made Zimmerman sound racist.

"We have launched an internal investigation into the editorial process surrounding this particular story," the network said in a statement to the Washington Post on Monday.

NBC's "Today" show ran the edited audio of George Zimmerman's phone call to a police dispatcher in which Zimmerman says: "'This guy looks like he's up to no good … he looks black."

But the audio recording in its entirety reveals that Zimmerman did not volunteer the information that Martin was black. Instead, Zimmerman was answering a question from a police dispatcher about the race of the "suspicious person" whom Zimmerman was speaking about.

A transcript of the complete 911 call shows that Zimmerman said, "This guy looks like he's up to no good. Or he's on drugs or something. It's raining and he's just walking around, looking about."

The 911 officer responded saying, "OK, and this guy — is he black, white or Hispanic?"

"He looks black," Zimmerman said.

The abridged conversation between Zimmerman and the dispatcher that NBC ran on March 27 has been blasted by media watchdog groups as misleading. Critics have said the edited version was made to suggest that Zimmerman targeted Martin because he was black -- an accusation by many that is still under investigation.

Martin, 17, was shot to death Feb. 26 by Zimmerman, 28, a neighborhood watch volunteer, as Martin walked from a convenience store back to his father's fiancee's home in a gated community outside Orlando. The case has stirred a national conversation about race and the laws of self-defense.

Martin, a black teenager from Miami, was unarmed when he was shot by Zimmerman, whose father is white and mother is Hispanic. Zimmerman told police the teen attacked him before he shot in self-defense. He has not been charged in the case, despite repeated calls by political leaders and protesters for his arrest.

NBC has also come under fire by some critics for allowing MSNBC personality, the Rev. Al Sharpton, to lead protests in Florida calling for Zimmerman's arrest. Sharpton is scheduled to speak Monday in Sanford, Fla., at a march of about a thousand people carrying signs and wearing T-shirts with the teen's image.

The Associated Press contributed to this report.