In Greensboro, N.C., the violence has gotten so extreme that a shootout erupted in front of the county courthouse the other day, across the street from the sheriff’s office, leaving a 20-year-old man dead. Greensboro set a city record with 45 homicides last year, and, as of Friday, already had 54 this year.

“We’ve always had a level of gang activity,” Greensboro Police Chief Brian James said in an interview, “but it’s more prolific now. I’m not sure what’s changed, but the offenders are more bold than they’ve ever been.”

Homicides across America rose more than 28 percent in the first nine months of this year, and aggravated assaults increased nine percent, while rapes and robberies saw significant drops compared to the same period last year, according to statistics compiled this month from 223 police agencies by the Major Cities Chiefs Association and the Police Executive Research Forum.

Some police commanders say the twin impacts of the coronavirus and civil uprisings against police violence caused them to redirect their officers away from proactive anti-crime programs, whether due to virus-related budget cuts or strategic redeployment of forces to handle the unrest. Other officials point to job loss and other stresses of the pandemic as fueling tension and leading to violence. And with many schools shuttered, police say, many areas have seen a rise in violence involving juveniles.

Fort Worth saw a 66 percent increase in killings in the first nine months of the year, and Boston recorded a 52 percent jump. Cities that experienced tumultuous protests in the wake of police killings saw some of the highest homicide spikes: Minneapolis’s total went from 33 in the first nine months of last year, to 61 this year, an 85 percent increase. Louisville has seen a 79 percent increase, Portland a 68 percent increase, and Milwaukee’s homicides have more than doubled, from 67 to 141, a 110 percent increase.

“We haven’t seen numbers like this since the ’90s,” said PERF Executive Director Chuck Wexler. “We’ve had 20 years of steady declines in crime. Is this just an aberration, or does this portend something for the future? This has been under the radar because of the pandemic, but something’s happening across the country in the most serious crimes. The next administration, they’re going to have to pay serious attention to this.”

In the Washington region, the numbers are mostly bad: D.C. police reported homicides up 13 percent in the first nine months of 2020, and Prince George’s County is up 58 percent, while Montgomery and Fairfax counties have also seen increases. But in both Baltimore City and Baltimore County, homicides and aggravated assaults have actually declined from the same period last year.

The Major Cities Chiefs first surveyed 67 big-city police departments, finding an aggregate 28.7 percent increase in slayings and 10.6 percent rise in aggravated assaults, but a nearly 17 percent decline in rapes and a 10.5 percent drop in robberies.

PERF then obtained data from another 156 agencies, ranging from departments with fewer than 50 officers to those with more than 250 officers. Combining the smaller jurisdictions with the larger ones from the Major Cities survey, PERF found the numbers were the same: 28.2 percent rise in homicides, 9.3 percent increase in aggravated assaults, with similar double-digit drops in rapes and robberies.

In Kansas City, Kan., homicides have risen from 23 to 40, and aggravated assaults are up 75 percent. “People are in crisis,” Wyandotte County District Attorney Mark A. Dupree Sr. told The Post. “We’ve had so many people stuck in their homes, not going to work, not going to church. Just sitting idle, and like my grandmother used to say, ‘Idle hands are the devil’s workshop.’ We’re seeing people dying of silliness, for no reason. A year ago, we weren’t seeing that.”

About 73 percent of big cities reported decreases in robberies, and 86 percent have seen drops in rapes. “With fewer people out and about, there are fewer opportunities to commit robberies,” Houston Assistant Chief Heather Morris told PERF.

But Houston’s homicide total is up 35 percent, and Morris blamed bail reform for some of that. “We had 28 suspects last year who were on bond or parole when they committed a murder,” Morris said, “and this year we’ve had 44. The person who killed one of our officers a week ago was out on $100 bond for unlawfully possessing a weapon. . . . Bond reform in some cases is needed, but you have people who allegedly committed violent crimes getting out on bond when they haven’t in the past.”

Of the large cities surveyed, 70 percent had an increase in homicides, 21 percent had a decrease, and nine percent had no change. Including all 223 agencies surveyed, 58 percent saw a rise in homicide, 20 percent had decreases, and 22 percent — mostly smaller agencies — had no change.

The survey’s findings continue a trend in 2020 first diagnosed by Richard Rosenfeld, a criminologist at the University of Missouri-St. Louis, in a July study of 27 U.S. cities. Property crimes such as burglary and auto theft dropped, but homicides and aggravated assaults were already showing significant rises by June. Rosenfeld likened the trend to crime increases that occurred in the aftermath of police violence and protests in Ferguson, Mo., Baltimore and Chicago in 2014 and 2015, in which “de-policing” as a reaction to the protests enabled more crime, and that police lost legitimacy and trust in minority and poorer communities.