Correction: An earlier version of this article incorrectly said that NBC asked D.C. police for an ammunition clip to use as a prop on a Sunday show. It actually asked for permission to use such a clip.

The host of NBC's “Meet the Press” displayed what appeared to be a high-capacity ammunition magazine on national television Sunday, embroiling the network in controversy and leaving D.C. authorities to decide whether a crime was committed.

The show’s host, David Gregory, held up what he described as a magazine that holds 30 bullets as he questioned National Rifle Association chief executive Wayne LaPierre about the Dec. 14 massacre in Newtown, Conn.

D.C. gun laws prohibit possessing a “large capacity ammunition feeding device” — defined as holding more than 10 rounds — regardless of whether it is attached to a firearm and whether there are bullets in it. The offense is a misdemeanor punishable by up to one year in jail and a $1,000 fine.

Viewers e-mailed D.C. police after watching the segment, asking them to arrest Gregory. In an e-mailed response to the Patriot Perspective blog, police wrote:

“NBC contacted [D.C. police] inquiring if they could utilize a high capacity magazine for their segment. NBC was informed that possession of a high capacity magazines is not permissible and their request was denied. This matter is currently being investigated.” A police spokeswoman confirmed that the e-mail was authentic.

Gregory appears to have used a large-capacity ammunition magazine anyway. A police official said detectives will try to determine whether it was real, how it was obtained and whether the segment was filmed in the District. The official said the investigation will entail questioning NBC producers and could conclude this week.

NBC News, through a spokeswoman, declined comment.

The situation presents authorities with an unusual decision: file charges in a crime that is infrequently prosecuted or appear unwilling to enforce the District’s gun laws. Gun rights advocates were among those who called police to complain.

“The police are in a public relations quandary,” said David Benowitz, a defense lawyer who handles gun cases in the District, Maryland and Virginia. “The question is going to be to what level of knowledge did David Gregory have that this was potentially an illegal act. . . . I presume David Gregory didn’t go out on the street and get a 30-round clip himself.”

“Maybe the NRA can fund his defense,” he joked.

Gregory used the prop as he posed a question to LaPierre in a segment that is posted on the MSNBC Web site.

“Here’s a magazine for ammunition that carries 30 bullets,” Gregory says. “Now, isn’t it possible that if we got rid of these” — he sets it down and picks up a smaller one — “if we replaced them and said, ‘Well, you can only have a magazine that carries five bullets or 10 bullets,’ isn’t it just possible that we could reduce the carnage in a situation like Newtown?”

“I don’t believe that’s going to make one difference,” LaPierre replies.

The D.C. attorney general’s office, which could decide whether to file charges, declined to comment.

Politicians and news anchors have long used guns as props. In 1993, then-Maryland Gov. William Donald Schaefer (D) pointed an unloaded pistol, provided by the Maryland State Police, at an unknowing Associated Press reporter during a news conference as he attempted to show the dangerous nature of firearms he wanted to have banned. Schaefer was not charged with a crime.

Erik Wemple and Martin Weil contributed to this report.