Violent crime is on the rise in the US capital, where a 28-percent uptick in homicides this year has left researchers perplexed and politicians pointing fingers.

And while Washington is still a far cry from its days as the "murder capital" of the United States, amid the 1990s crack epidemic, the rise in violent crime in the city is both causing consternation among residents and dividing them.

Some of the killings have been especially grim: a 10-year-old girl who died from a stray bullet on Mother's Day; an Afghan immigrant who, having fled his country after the Taliban took over, was shot to death while working a late shift as a Lyft driver.

Puzzling researchers is the fact that Washington's murder rate has jumped while other major metros in the United States have seen declines. Also, the number of armed carjackings in the city has more than doubled, according to police statistics.

- 'Outlier' among US cities -

"DC is something of an outlier with respect to homicide trends," when compared to cities like New York, Philadelphia, Chicago or Baltimore, says Richard Rosenfeld, a criminologist at the University of Missouri-St. Louis.

Rosenfeld added that the explanation behind the uptick "remains something of a mystery."

Meanwhile, Joseph Richardson, a professor at the University of Maryland who studies violence prevention programs in Washington, has several theories.

"We can speculate that there may be a few things that are happening," he tells AFP, including a recent change in police leadership. He also suspects the number of shootings linked to drug trafficking is underestimated.

Another theory is the destabilizing effect of gentrification.

As certain neighborhoods improve, poor renters can be priced out. In the United States, where poverty often falls along racial lines, it's frequently Black Americans who are uprooted.

But some arguments put forward by authorities and politicians -- such as a lack of police officers, or the fact that two-thirds of arrests aren't followed up with prosecutions -- don't convince Rosenfeld, the criminologist.

And Washington is hardly the only city in the United States awash with guns.

Rather, "it appears that Washington has recovered more slowly from the dislocations of the pandemic than many other cities," he says, leaving certain areas that were once "congested with pedestrians... relatively empty as a result."

- 'A haven for crime' -

The city is a far cry from where it was in the 1980s and 90s, when entire swaths of Washington were considered dangerous. Both international and domestic tourists still flock to the city's flower-filled streets, and many residents can claim a high quality of life and easy access to amenities.

Yet things have changed enough to alter some Washingtonians' habits, like those who now avoid going to gas stations at night, worried about carjackings.

The consular section of the Embassy of Mexico issued a statement on social media warning that the city "is experiencing a significant increase in crime in areas previously considered safe."

One restaurant in Washington posted on X, formerly Twitter, calling for help as the corner it sits on becomes "a haven for crime and harassment."

- They 'let it happen' -

Debates on why crime has risen and what to do about it have become hot-button political issues in a country whose instances of police brutality have at times shocked the world.

Pamela Smith, named the local police chief this summer, has called for an "all-government approach" at a moment where "there seems to be an uptick in our juveniles committing some of these crimes."

City council member Trayon White, meanwhile, caused a storm when he called for the deployment of the National Guard.

In March, Republicans in Congress summoned city officials for a hearing, accusing the Democratic-majority city of being "soft on crime."

But Jada, a 28-year-old Black security guard who works downtown and preferred not to give her last name, wondered if politicians and authorities actually care about crime in the city.

"Homicide rates, I feel like it's mostly Black-on-Black crime," she told AFP. "Because it's Black-on-Black or it is Hispanic-on-Hispanic, I don't feel like they care. I feel like they're just going to let it happen."

Whether they care or not, the killings aren't stopping: on Monday, in the southwest of the city, where Jada lives, yet another teenager was killed in a shooting.