In the weeks after the death of Philando Castile, a black man who was shot by officer Jeronimo Yanez on July 6, 2016, the Associated Press reported nearly half of the people arrested by the St. Anthony Police Department, Yanez’s employer, were black.

That number had been on the rise since nearly every year since at least 2011, in a patrol area where just 7 percent of the population is black and a metro area where just 8 percent of the population is black.

The death of Castile marked the first time a Minnesota police officer had been charged in an on-duty shooting since at least 2005, though a jury found him not guilty on all three charges — second degree manslaughter and two felony counts of intentional discharge of a dangerous weapon — last month.

Officer-involved shootings of Castile and other black people have sparked local and national discussions about how to change relations between police and communities of color, officer training and department culture.

By one measure — arrests — things in St. Anthony may be changing, at least a little. After Castile’s death, the share St. Anthony Police arrestees who were black declined for the first time in several years, MinnPost learned from data obtained under a data practices request.

The share increased from about a third in 2011 to more than 45 percent in 2016, according to the St. Anthony Police Department’s data, but dropped a couple percentage points to 43 percent so far this year.

That’s still significantly higher than the share of the population black people make up in the metro, but represents a dip in a trendline that has generally gone up.

The St. Anthony Police Department declined to speak to MinnPost and the police chief, mayor and members of the city council did not respond to requests for comment, but here’s what experts offered as possible explanations for the drop.

Have officers changed their behavior since the shooting?

First, it’s possible that officers in the department changed their behavior in the wake of Castile’s death.

Research suggests the publicity over high-profile police shootings and police-community relations have changed police attitudes and behavior nationally.

A Pew Research survey released in January found that 86 percent of officers found their jobs more difficult in the wake of high-profile police shootings across the U.S. Three in four say colleagues are more wary of using force “when appropriate” and to question people who appear suspicious.

Related to Castile’s death or not, the total number of arrests declined after July 6th. St. Anthony Officers made 1,002 arrests before and during that day, and just 542 after. In 2015, there were 1,052 arrests made on or before July 6, and 1,077 after.

Between Jan. 1 and June 30 of this year, there were 617 arrests.

Is it also possible the way police made arrests changed in the wake of the shooting?

An arrest slowdown wouldn’t be without precedent. Following the release of a video showing the police killing of Laquan McDonald, a teenager who was carrying a knife and walking away from police, in Chicago, that city saw a decline in Terry stops, when officers stop citizens on a reasonable suspicion of criminal involvement, according to a paper by Jeffrey Fagan, a professor at Columbia Law School, and colleague Daniel Richman. As tensions rose over the death of Michael Brown in Ferguson and Freddie Gray in Baltimore, Baltimore saw a slowdown in arrests for less serious felonies and misdemeanors.

“The pullback is part of a loosely coupled system of distrust and resentment between citizens and police that entwines violence, cynicism and public safety into a complex and tangled ecology,” Fagan and Richman write.

Has the St. Anthony Police Department taken steps to change officers’ behavior?

The deaths of Castile and others have set off a lot of discussion about what police departments can do to ensure shootings like this don’t happen again. Police departments across the U.S. have discussed and in many cases increased efforts at community policing, and changing use of force policies.

“It could also be that police department policy has changed — that decisions are being made about how officers are deployed, how they act with the public, when arrests are appropriate, etc., and officers are following those changes,”  wrote David Harris, a professor at the University of Pittsburgh School of Law, in an email.

MinnPost reached out to Police Chief Jon Mangseth by email to ask if the St. Anthony Police Department was considering or had changed policies, but he didn’t respond. A person who answered the phone at St. Anthony Police headquarters said the department wouldn’t comment.

The department has shown an interest in reviewing its policies. In December, it signed on to be part of a federal Department of Justice program to review and improve policy.

As part of the process, the DOJ will review the department’s traffic, recruitment, community relations and accountability, a to-do list that grew out of community listening sessions.

A review of DOJ activities under new Attorney General Jeff Sessions will not stop the department’s day-to-day work in St. Anthony, a department spokeswoman wrote in an email.

In terms of training at the department, its 2016 annual report mentions bias awareness training completed in the second half of 2016, plus outlines for 2017 de-escalation training, community relations work and work with the Department of Justice.  

Have black people changed behavior in response to the shooting?

Arrests happen because people interact with police. If fewer black people are interacting with the St. Anthony Police, fewer black people are likely to be arrested.

Rashad Turner, a founder of Black Lives Matter St. Paul and childhood friend of Castile, told Time that the area where Castile was killed was already a place that black people tried to avoid out of fear.

“Where Phil was killed, this is an area that historically has been an area that black people, people of color, avoid,” he said. “When they see us, they see us as an opportunity to go fishing.”

There isn’t a lot of hard evidence to back up the idea that this happens following a high-profile incident like Castile’s death, Fagan said, but anecdotally, it can happen.

A dropoff could be partly due to black people staying away from the area, traveling in groups to avoid being stopped individually, or taking taxis or Uber, Fagan said.

Could there be another explanation?

As we touched on before, arrests happen when behavior is reported to or observed by police. If any number of behaviors has changed — by people of any color or police — for any reason, data on arrests by race could differ from previous years. It’s also important to note that it’s only been one year since the shooting, so we don’t know what the trendline will look like into the future.

Correction: A previous version of this story incorrectly described the Laquan McDonald incident. McDonald was carrying a knife.