KOKOMO, Ind. — There’s a Colt Thompson submachine gun on display inside the police department in Tucson, Arizona. Officials there say it belonged to John Dillinger, one of the most infamous gangsters in U.S. history who was deemed Public Enemy No. 1 by the FBI.

But according to city officials in a small town in central Indiana, there’s just one problem: The gun didn’t belong to Dillinger, and it doesn’t belong to the Tucson Police Department.

They say it belongs to Peru, Indiana.

Josh Sigler, an administrative assistant to Peru Mayor Gabe Greer, said after conducting extensive research, he’s convinced Dillinger brazenly stole the gun from the Peru Police Department in October 1933, along with other weapons and police equipment.

When Dillinger was finally apprehended by Tucson police three months later, they confiscated the submachine gun, commonly referred to as a Tommy gun. They kept it and have never given it back, Sigler said.

He said the proof is the serial number on the gun, which is 5878. According to a notice issued by the Peru police chief after the robbery, that was the serial number on the weapon stolen by Dillinger.

That’s been confirmed by research completed by Gordon Herigstad, who published a book called “Colt Thompson Submachine Gun Serial Numbers & Histories.” The book details the narrative of every submachine gun that was ever manufactured outside of wartime production – all 15,000 of them.

According the book, Tommy gun 5878 was purchased and shipped to the Peru Police Department in 1929, along with a second Tommy gun with the serial number 7117.

Dillinger and his gangster accomplice, Harry Pierpont, robbed the police station, stole the Tommy gun, and then used it to hold up the First National Bank of East Chicago on Jan. 15, 1934, according to the book. The gun was captured with Dillinger in Tucson on Jan. 25, 1934.

The second gun avoided capture at the time of the holdup. The gun had jammed earlier that day and had been taken apart and put in a drawer. The Peru Police Department still has that weapon.

Sigler said with two sources citing the serial number of the stolen Tommy gun, and Herigstad’s research confirming it wound up on display at the Tucson police department, it’s clear that the gun belongs to Peru.

“[Herigstad] spent his whole life searching archives and talking to people, and this is what he found for our two guns,” he told the Kokomo, Indiana Tribune. “To me, that’s pretty definitive proof that 5878 is ours.”

So how did Dillinger knock off the police department and steal the gun?

City Attorney Pat Roberts knows the story of Dillinger’s robbery well. His father, Eddie Roberts, was one of the officers on duty at the time of the robbery.

According to the story told by his father, Pierpont came into the station on Oct. 20, 1933, posing as an insurance agent. He asked officers to show him all the guns so he could give them a quote on insuring the weapons.

At around 11:30 p.m., Dillinger, Pierpont and other members of the gang raided the department.

As the story goes, Dillinger lined up the three officers on duty, including Roberts, at gunpoint. He had Roberts buzz them into the room where the weapons were held. While he was doing that, Dillinger ripped off his badge and took his pistol.

After looting the arsenal, which included a sawed-off shotgun, pistols, pump rifles, a bullet-proof vest, a pair of handcuffs and the Tommy gun, the gang told the officers to wait in the building for 15 minutes. If they left before then, Dillinger threatened to shoot all of them.

As the officers waited, the gang jumped in their getaway car and fled, never to be seen in the town again.

The Peru heist was part of a string of high-profile robberies pulled off by Dillinger and his gang in late 1933. The crew also robbed the police stations in Lima, Ohio, and Racine, Wisconsin, and knocked off other places in Indiana, including Warsaw, Montpelier and Greencastle.

The crime spree came to an end in Tucson, where the gang had holed up in The Hotel Congress.

On Jan. 22, 1934, while the gang was there, the hotel caught fire. Dillinger was identified by the firefighters and taken into custody. All the weapons he’d stolen during his crime spree in the Midwest were confiscated.

Although some of the guns were returned to the places where they had been stolen, the Tommy gun from Peru never made it home, according Herigstad’s research.

His book reports there was apparently “some friction” between the governors of Indiana and Arizona, which may have contributed to the gun staying in Tucson.

Sigler said whatever the reason, it’s time for the gun to return home.

“It’s our gun,” he said. “It’s an important piece of our history, and it’s worth a lot of money. I feel like Tucson should give it back. Just because some gangster took it out there and they confiscated it doesn’t mean it’s theirs.”

But getting the gun back won’t be an easy undertaking.

Sigler said he talked to officials at the Tucson Police Department, and they weren’t convinced by his story.

City attorney Roberts, who is providing legal counsel in the case, said as it stands now, he doesn’t think there’s enough documentation to legally demand that the gun be returned.

Although they have the serial number, they also need a copy of the purchase order to make their case air tight, he said.

Sigler said he’s currently trying to track that down to help build their argument.

Roberts said once they have enough documentation to prove beyond a reasonable doubt that the gun belongs to the city, he plans to send Tucson a letter requesting the weapon’s return.

“Document, document, document, and then we can say, ‘See, here it is, we believe that gun is ours,’” he said. “‘Will you please send it back?’ Hopefully we’ll be successful in getting it back. Hopefully they’re in the mood to give it back.”

“It’s a part of Peru’s history,” he said Peru Police Chief Mike Meeks. “I think it’s important for us to have since it belonged to us. It will be interesting to see how it all plays out.”

Gerber writes for the Kokomo, Indiana Tribune.