Attorney General Eric Holder, left, and Rev. Al Sharpton, host of MSNBC's "Politics Nation." (AP Photo)

(CNSNews.com) – Attorney General Eric Holder praised left-wing activist Rev. Al Sharpton at the opening of the National Action Network (NAN) convention on Wednesday, and also stressed that the Justice Department is conducting a thorough investigation of the fatal Trayvon Martin shooting that “will examine the facts and the law.”

Sharpton, president of NAN and host of MSNBC’s Politics Nation, has led several rallies demanding the arrest of George Zimmerman, who reportedly shot Martin on Feb. 26. On Mar. 30 in Sanford, Fla., where the shooting occurred, Sharpton pledged that his group would “move to the next level if Zimmerman isn’t arrested.”

At the opening of NAN’s 14th annual convention in Washington, D.C., the attorney general first thanked MSNBC’s Rev. Sharpton “for your partnership, your friendship, and your tireless efforts to speak out for the voiceless, to stand up for the powerless, and to shine a light on the problems we must solve, and the promises we must fulfill.”

Concerning Trayvon Martin, Holder said, “I know that many of you are greatly -- and rightly -- concerned about the recent shooting death of 17-year-old Trayvon Martin, a young man whose future has been lost to the ages."

"As most of you know, three weeks ago, the Department of Justice launched an investigation into this incident, which remains open at this time, and prevents me from talking in detail about this matter," he said.

“Although I cannot share where current efforts will lead us from here, I can assure you that, in this investigation – and in all cases – we will examine the facts and the law,” said Holder. “If we find evidence of a potential federal criminal civil rights crime, we will take appropriate action. And, at every step, the facts and the law will guide us forward.

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The National Action Network, which Sharpton founded, has held multiple rallies about the Martin shooting, largely critical of shooter George Zimmerman, irrespective of an ongoing investigation.

Zimmerman, who has not been arrested in the case, said he acted in self-defense after following Martin on Feb. 26, the night Martin was killed. A Florida special prosecutor announced on Monday that the case will not be taken before a Florida grand jury, though the investigation will continue. The FBI and Justice Department are also pursuing their investigations.

MSNBC’s Sharpton has led several rallies, shouting “Arrest Zimmerman Now!” and has called for civil disobedience and an “occupation” in Sanford, Fla., if an arrest is not made.