In the years after Hurricane Katrina, killings across East Baton Rouge Parish rose dramatically, giving the capital city a homicide rate that eclipsed many other major cities.

Since then the annual murder tally has shrunk. Homicides now occur at a slightly lower rate than the year before the storm.

But perhaps what’s lingered is a perception that crime in Baton Rouge skyrocketed after Katrina because of the influx of New Orleanians, who made up the majority of some 235,000 people displaced to the city in the days immediately after the disaster. While Baton Rouge law enforcement statistics show there was a crime spike, the idea that New Orleanians were to blame is outright wrong, said several current and former police officials and crime experts.

“I don’t accept the argument that these were these invaders from outside. No, no, no, no,” said LSU criminologist Ed Shihadeh. Key perpetrators from 2006 to 2009, when crime rose, were found to be longtime Baton Rouge residents, he said.

Matthew Lee, an LSU criminologist who’s now the vice provost for academic programs, said he’s “never seen a single stitch of systematic evidence to suggest” that criminal gangs migrated en masse to Baton Rouge.

As East Baton Rouge Parish Sheriff Sid Gautreaux put it recently, “We had our own homegrown criminals here to begin with.”

Instead, law enforcement and criminologists say there was a tangle of complicating factors to explain the uptick in violent crime in the years after Katrina, which along with murder, included increases in assaults and robberies. While a small component of this trend may have been evacuees committing crimes, law enforcement and experts say they more crucially saw a change in tactics that made the crime on the streets harder to combat, such as the targeted killing of witnesses.

And while crime — most notably homicides — has since decreased, some say that hasn’t made policing any easier.

“Our numbers are down, but our cases are more complicated,” said East Baton Rouge Parish District Attorney Hillar Moore.

Crime in crisis

In the early days after Katrina, as people from New Orleans found their way to Baton Rouge, Mayor-President Kip Holden famously issued a public warning to any “thugs” who had come to his city.

“We do not want to inherit the looting and all the other foolishness that went on in New Orleans. We do not want to inherit that breed that seeks to prey on other people,” he said.

Holden’s comment seemed to reflect an initial trepidation about the influx of new people into the city, but he later took it back. The mayor recently clarified that by “thugs,” he was referring to the looters he saw on TV in New Orleans, not anyone in Baton Rouge.

While the city population swelled in particular right after the storm, crime statistics show the largest increase — particularly for murder — wasn’t in 2006, but a year later.

Homicides per capita in East Baton Rouge Parish reached 21 per 100,000 people in 2007, up from 14.5 per 100,000 in 2004. In comparison, killings per capita across the parish in 2014 were back down to 14 per 100,000, according to local law enforcement agencies and crime analyst Jeff Asher.

It’s not uncommon for crime to increase during a crisis, officials and experts said.

“When things get disorganized, crime rates go up,” said Shihadeh, explaining the basics of what sociologists call social disorganization theory. “It happened here, it happened in old Chicago, it happened in Baghdad the weeks after we invaded.”

Baton Rouge more or less doubled in size within a matter of days after Katrina, although people did not necessarily stay for extended periods. A study Shihadeh conducted found about half of capital city households sheltered evacuees, a testament to Louisiana’s exceptionally strong kinship-based society, he said.

But with that came an intense strain placed on local communities.

“This was one of the largest mass migrations in recent history,” said Lee. When longtime residents see an overwhelming number of new neighbors, “it makes them feel like there’s sort of an ‘us’ and a ‘them.’ ”

Lack of familiarity can erode the normal social interactions that prevent crime, Lee explained.

“You may have groups of people coming in that have different expectations for behavior in public, for example. Or, when people don’t know each other as well ... they may be less willing to intervene in pre-criminal behavior in public space,” such as speaking up about defaced buildings, Lee said.

Baton Rouge Police Chief Carl Dabadie said he thinks it’s ill-advised to draw any stark conclusions about who causes crime.

“I think you had a very traumatic incident that happened that displaced a lot of people, that put a lot of people outside of their comfort zones,” he said. “It put stresses on people. It put stresses on the cities where those people went to.”

‘Sophisticated’ crime?

Tracing the ways Baton Rouge crime changed after Katrina instead points to more vicious, big-city tactics that may have been exacerbated by the population influx, experts said.

“Before that, people would rob you, but they wouldn’t harm you. They were just robbers. But then a change came where, ‘I’m not only gonna rob you, I’m gonna shoot everybody,’ ” said Jeff LeDuff, the police chief during the storm.

Televised crime shows trumpeting the power of DNA and ballistics analysis made criminals more wary of leaving behind evidence, he said.

One factor could have been the sliver of Katrina evacuees who were criminals. A small “criminal element” is present within any group, said Shihadeh, and some who came after Katrina might have influenced existing criminals in Baton Rouge.

As Moore, the district attorney, sees it, some New Orleanians made crime here more “sophisticated” by showing “our bad guys how to commit crimes of violence, and how to intimidate witnesses, do harm to witnesses or just kill them.”

Still, Shihadeh said additional factors should be considered. “The spike in crime that occurred after Katrina actually began before Katrina,” he said. One element, he said, was that there was an unusually large number of teenagers around the time of the storm, due to a surge in teen fertility 15 years prior, making a cohort that often gets into trouble more numerous.

Despite the more complex nature of crime in the parish, the murder rate has dropped fairly steadily, from some 92 parishwide killings in 2007 to 80 in 2010 to 63 last year.

A 2015 report coordinated by the Baton Rouge Area Foundation found that only 45 percent of local residents are afraid of becoming a crime victim this year, down from 62 percent in 2012.

One of the untold stories of evacuees coming to Baton Rouge after Katrina, Holden said in a recent interview, was how the city embraced many newcomers for the long term, after the initial turmoil faded.

“There was always this dividing line somewhere between Baton Rouge and New Orleans, but there were a lot of people, and a lot of people still here, who said they did not realize how nice this city was,” he said.

Follow Maya Lau on Twitter, @mayalau.