Updated

NBC journalist David Gregory won't face charges for displaying a high-capacity ammunition magazine on his "Meet the Press" news show, prosecutors announced Friday.

The city's office of attorney general, which handles low-level crimes, said criminal charges wouldn't serve the public's best interests even though possession of the magazine — capable of holding up to 30 rounds of ammunition — was clearly against the law. In a letter to NBC's lawyer, D.C. Attorney General Irvin Nathan also said he recognized that the device was intended as a prop to provoke public discussion on gun control following the Connecticut school massacre.

"Influencing our judgment in this case, among other things, is our recognition that the intent of the temporary possession and short display of the magazine was to promote the First Amendment purpose of informing an ongoing public debate about firearms policy in the United States, especially while this subject was foremost in the minds of the public" after the shooting and President Barack Obama's address to the nation, the letter said.

Firearms laws in the nation's capital generally restrict the possession of high-capacity ammunition magazines, regardless of whether they're attached to a firearm. D.C. police say NBC asked for permission to use the clip during a segment and was advised that it would be illegal. Gregory held up the magazine during a December 23 interview with Wayne LaPierre, the executive vice president of the National Rifle Association.

"Here is a magazine for ammunition that carries 30 bullets. Now, isn't it possible that if we got rid of these, if we replaced them and said, 'Well, you can only have a magazine that carries five bullets or ten bullets,' isn't it just possible that we could reduce the carnage in a situation like Newtown?" Gregory asked, referring to the Dec. 14 school shooting in Newtown, Conn., in which a gunman killed 20 children and six adults.

LaPierre replied: "I don't believe that's going to make one difference. There are so many different ways to evade that even if you had that" ban.

Police began investigating after the show aired and recently referred its findings to the office of attorney general.

Gregory, a longtime correspondent, was named "Meet the Press" moderator in 2008. The show is generally taped in Washington.