WASHINGTON D.C., April 23, 2007 – Congressman Todd Tiahrt is used to controversy. Now though, he's the focus of it.

An ad now playing on some airwaves attacks legislation sponsored by the congressman, which governs a national database that tracks multiple handgun sales.

The amendment, which has been renewed by Congress for four years, ensures that only federal law-enforcement officials have access to the data. Here is the ad in its entirety.

"A few years ago, I had the absolute worst nightmare of any police chief," Chief Scott Knight, Chaska, Minnesota Police Department, said. “One of my officers was shot. The Tiahrt Amendment has absolutely stood in the way to effectively address gun crime. Where are the guns coming from? Who's buying them? How are they getting into my city? The information is there. We're not allowed to have it. We're fighting criminals and illegal guns. Why is Congress fighting us?" Knight said.

Tiahrt says the ad is unfair since the amendment was endorsed by the Bureau of Alcohol, Tobacco and Firearms, and The Fraternal Order of Police, which said making the data public would only help criminals.

"The Tiahrt Amendment was aimed at protecting undercover officers and sting operations that try to take illegal guns off the streets," Tiahrt said.

The ad is backed by the group "Mayors Against Illegal Guns," co-founded by New York Mayor Michael Bloomberg. He believes local police should know the origin of weapons used in their city limits. Tiahrt says Bloomberg may have other motives.

"Well, I think it's politically motivated this year," Tiahrt said. "I think Mayor Bloomberg is either positioning himself to run for president as an independent, or if Sen. Clinton would win, he (Bloomberg) would run for senate in New York."

Meantime, while we showed you the ad in the context of a newscast, KSN has elected not to run it during regular programming because the station could not verify its claims. Broadcast stations are responsible for the content of issue advertising.