As he sold four handguns in a South Side parking lot last year, Levaine Tanksley boasted to his customer that there were plenty more illicit weapons available, investigators say.

"Twenty-five more in four hours," Tanksley told his customer, who was secretly working for law enforcement and recording the conversation. "Give me $5,000 and you can put your order in then. I'll get you whatever, give me a list."

As Tanksley, who police say has ties to a Chicago street gang, made his sales pitch, David Lewisbey was stocking up on more weapons at a gun show 40 miles away in Crown Point, Ind., one of several trips he made across the state border and back in little more than a day, according to federal authorities. Five hours later, Lewisbey, an unlikely gun trafficker then enrolled in college, was back in Chicago as Tanksley made good on his promise and sold the informant nine more guns, authorities allege.

A federal indictment charges the two with illegally selling 43 firearms to the government informant in just under 26 hours, a volume made possible by gun shows and less restrictive state laws in Indiana, by far the No. 1 source of out-of-state guns used in crimes in Cook County. Private gun sales in Indiana don't require background checks, a waiting period or even a record of the transaction.

The scheme exposed by law enforcement illustrates the tidal wave of illegal guns confronting Chicago police as they battle surging numbers of homicides and shootings. With the country poised to respond to gun violence stretching from a first-grade classroom in Newtown, Conn., to Harsh Park on Chicago's South Side, allegations of the duo's lucrative enterprise provide a textbook example of how criminals can exploit existing gun laws to put society's most vulnerable at even greater risk.

"(Lewisbey) would go travel to Indiana, to these gun shows where he would load up literally a duffel bag, go from table to table paying in cash, large amounts of cash … before returning right into the worst neighborhoods of Chicago," Assistant U.S. Attorney Christopher Parente said at a recent detention hearing in federal court. "He would sell them literally in the back alley and on the side streets."

'An arms bazaar'

K's Merchandise, a big-box department store on a busy commercial strip outside Fort Wayne, Ind., has been shut for sometime. But on a recent Friday, a crowd swelled inside as shoppers slowly browsed hundreds of tables under bright fluorescent lights.

Gone were jewelry cases and electronics. Instead, spit-shined Sig Sauers, Glocks, Berettas and Rugers were spread across tables in neat rows. For collectors, there were novelties like an 1881 French pistol, Dirty Harry-style .44 Magnums and a Browning small enough to tuck into a palm. Rifles were perched on racks with care. One man walked the floor with an AR-15 slung on his back, a white flag poking out of the barrel offering it up for sale.

Some customers gripped the handguns for a feel and chatted with friendly, folksy sellers. Families strolled among the mostly male crowd, and there was a gathering space in the back to grab coffee, a chocolate bar or a hot dog.

The atmosphere was friendly and small-town — almost like a farmers market.

Tucked among many of the weapons displays were signs in bold lettering that read "Private Sales," "Cash Only" or "Private Collections."

The signs signaled to shoppers that there wouldn't necessarily be a background check or paperwork involved in a purchase, a crucial element for an illegal gun-trafficking scheme and thus a highly troubling aspect of gun shows for law enforcement and gun-control advocates alike.

Some shows insist on background checks even for private transfers, but law enforcement experts said buyers and sellers commonly move transactions to the parking lot.

"They are like an arms bazaar," said Paul Helmke, Fort Wayne's former mayor and onetime president of the Brady Campaign to Prevent Gun Violence. "We make it very, very easy for dangerous people to get guns."

According to federal law, dealers who hold a federal firearms license must run a phone background check on gun buyers and have customers fill out Bureau of Alcohol, Tobacco, Firearms and Explosives Form 4473, promising they have no criminal background or mental illness, said ATF spokesman Thomas Ahern. But an Indiana resident who wants to sell or transfer a gun from his or her private collection only needs to see an Indiana state ID first. There is no limit to how many guns can be transferred.

And even dealers in Indiana don't have to make customers wait to take possession of a handgun. Illinois, by contrast, mandates a 72-hour waiting period.

Trail to Indiana

According to court documents, Lewisbey met a gun seller at the Indianapolis 1500 Gun and Knife Show in March 2012 and bought six guns after showing an Indiana state ID — although prosecutors believe the document was fake because Lewisbey lived in Illinois. Over the next two months, Lewisbey bought 30 to 40 more guns from the same person, including two exchanges at McDonald's parking lots in Indiana, the charges alleged.

Then, over a 26-hour period on April 22 and 23, Lewisbey teamed up with Tanksley to make five different sales to the informant, collecting $38,000 in cash in all, authorities said.

Lewisbey and Tanksley have both pleaded not guilty.

The number of guns Tanksley had access to stunned veteran law enforcement officers. Some believe it is one of the larger gun-running cases in recent history in Chicago. A task force including Chicago police officers, Illinois State Police troopers and ATF agents unraveled the scheme.

The trail led them straight over the border to Indiana, which has drawn increasing attention from law enforcement here.

"If you take the next five states after Indiana and add them up, they still don't equal the amount of guns that have come from Indiana," said Cook County Sheriff Tom Dart, who last week headed a "gun summit" in Gary that drew more than 25 Illinois and Indiana law enforcement agencies to talk about how to stem the tide.

"There is no law prohibiting us from having a covert presence at these shows, looking for license plates, trying to identify patterns (and) people selling out of their car trunks," Dart said. "The Constitution doesn't require us to close our eyes and jam our heads in the sand."