After all the dastardly deeds that Al Capone partook in during his days as America’s most famous crime boss—murder, bootlegging, gambling, and prostitution among them—it seems almost unfair that it was the not-so-nefarious crime of tax evasion that finally took him and his cronies down. But that doesn’t mean there weren’t guns involved. Specifically, a Smith & Wesson .38 Special, brandished by badass IRS Investigator Michael Malone, that you can see for yourself at The Mob Museum in Las Vegas beginning on April 17.

For the record: Michael Malone wasn’t just some tax cop stiff who happened to be in the right place at the right time in order to nab Capone. In order to make his case stick, he went undercover, infiltrating Capone’s gang for nearly three years.

“Michael Malone was, I believe, the greatest undercover agent in the history of law enforcement,” Paul Camacho, the former head of IRS criminal investigations and a dedicated agency historian, told Guns.com. “This was the riskiest assignment you could ever think of. People were dying left and right, witnesses were dying left and right. Nobody wanted to be with these guys.”

Malone and a group of U.S. Treasury Department agents known as “T-Men” spent years investigating the financial wrongdoings of some of the country’s most notorious gangsters, including Capone and Nucky Johnson (the basis for Steve Buscemi’s Nucky Thompson character in Boardwalk Empire). The gun will be part of “Follow the Money,” a soon-to-be-permanent exhibition that will include a number of letters, documents, photographs, and artifacts that will pay tribute to the work of these brave men, who proved that crime pays … until you’ve got the T-Men on your trail.

On October 18, 1931, Capone was convicted of tax evasion and sentenced to 11 years in a federal prison and fined more than $270,000 in fees and interest due on his back taxes. On November 16, 1939, Capone was released from prison after serving less than eight years. He never showed his face publicly in Chicago again; he retired to Miami's Palm Island, where he lived out his last years in seclusion. He passed away on January 25, 1947.