Donald Trump used his Republican convention speech last week to single out Chicago — the Obamas’ hometown — as a dystopia of urban violence. In remarks accepting his party’s presidential nomination, he said that “almost 4,000 have been killed” since Obama took over the White House nearly eight years ago.

Chicago is indeed a violent place, but Chicagoans — with some justification — say one factor in the high rate of gun violence is a steady flow of weapons from across the state line in Indiana, where Mike Pence, Trump’s vice presidential running mate, is the governor. Several analyses of gun arrests and data that trace a gun’s history, show that Indiana is the leading out-of-state source of illegal firearms for Chicago criminals.

Chicago has long been a battleground for warring factions of street gangs, with some estimates of gang membership as high as 100,000. The nation’s third largest city has struggled for years to curb a rash of nightly shootings, while its police department has been cited repeatedly for abuse. An oversight agreement with the Justice Department is expected soon.

“In the president's hometown of Chicago, more than 2,000 people have been the victims of shootings this year alone,” Trump told the convention in Cleveland. (The Chicago Police Department’s research division says that the city counted 1,845 shootings as of July 20. And there have been just over 3,500 murders since Obama’s 2009 inauguration).

Trump has criticized Chicago for years. A local news site, DNAinfo, recently highlighted several of Trump’s statements and Twitter posts, dating back to 2012. He has sent out messages that have characterized the city as a “shooting disaster,” and a place where “crime is out of control, and rapidly getting worse...Not good!”

But others have provided some context for a city awash in handguns. The University of Chicago and Duke University issued a report in 2015 that detailed “the importance of Indiana as a source of crime guns, particularly for gang members.” Researchers crunched five years’ worth of federal gun-tracing data, from 2009 to 2013, along with Chicago arrest information, and concluded that Indiana supplied up to one-third of confiscated guns in the city. The Trace, a website that reports on guns and gun violence in the United States last year rankedIndiana No. 1 among states that supply Illinois crime guns, using statistics from 2010 to 2014 from the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Pence, who took over the Indiana governor’s mansion in 2013, brushed off the criticism. “Blaming Chicago’s crime problems on Indiana is unfortunate and inaccurate,” replied Pence’s press secretary, Kara Brooks, when asked to explain what the state was doing to curtail illegal gun traffic. Trump’s campaign did not respond to a request for comment.

State laws make it easy for out-of-state visitors to buy guns in Indiana. There are no permits or licenses required to purchase a gun, or multiple guns, which lures Chicago's gang members who like to buy their weapons in bulk. Those who want to buy firearms in Illinois, meanwhile, are vetted by the state police before being issued a special identification card for weapons' owners.

Pence has an A grade as of 2012 from the National Rifle Association, and has boasted that he’s a “card carrying member of the N.R.A.”

Virginia, where Hillary Clinton’s running mate Tim Kaine has been a public official since 1994, has also been criticized as a place that’s part of an “iron pipeline,” a conduit for guns from relatively unregulated states, mostly in the South, to New York City. In 2013 Mayor Michael Bloomberg, citing 2011 data, identified Virginia as the leading state among ten where guns used in city crimes originated. But by 2015, a New York Times analysis found Virginia no longer was a leading exporter of illegal guns, though it was still a player in New York’s illicit gun market. Kaine, as mayor, governor and senator has been an aggressive champion of gun control. As the state’s governor in 2007, Kaine signed an executive order, in response to the Virginia Tech massacre, that allowed authorities to flag a mentally ill person during an attempted gun purchase. Last month, Kaine was part of the Senate filibuster that erupted after the mass shooting in an Orlando nightclub. He has earned an F grade from the gun lobby.