Police officers and investigators work outside a Hollywood Hills home where a fatal shooting occurred in Los Angeles, on Feb. 19, 2020.
CNN  — 

The number of homicides continues to rise in major American cities following a year that saw a record increase in homicides across the country, according to a report published Thursday by the Council on Criminal Justice.

A study of homicides during the first six months of this year in 22 cities showed that the number of murders increased by 16% compared to the same period in 2020 and by 42% compared to the first six months of 2019.

The report is the latest suggesting that the number of homicides in major American cities continues to grow.

The number of homicides in 2020 compared to 2019 rose by 25%, according to an FBI preliminary report. That represents the largest jump since the agency started releasing annual homicide figures in the 1960s.

Thursday’s study was released by the Council on Criminal Justice, a non-partisan think tank that advocates for “a fair and effective criminal justice system.”

The number of homicides in the studied cities is 259 greater than in 2020 and 548 greater than the same period in 2019. Gun assaults in those cities were up by 5% compared to 2020, and aggravated assaults rose by 9%. Drug and property crime fell, according to the group.

“What we’re seeing is that violent crime remains on the rise, but the rate of that rise is slowing,” said Thomas Abt, a senior fellow at the Council on Criminal Justice. “One can view this as good news or as bad news. Violent crime is increasing, but not as quickly as before. It’s important to keep in mind the context, which is that these trends are deeply disturbing but not a cause for panic.”

He added: “The absolute rates of homicide, not relative to last year, are still well below the sort of extreme highs of the late eighties and early nineties.”

The increase in violent crime is happening across many cities at the same time, according to Abt. It’s what he calls the “national effect.”

The two major events of last year, both the pandemic and protests that called for the abolition of police departments, are having an impact on crime. But how they are having an impact remains “difficult to untangle,” Abt said.

The domestic violence rate was 2% higher during the first half of 2021 compared to last year, with 2,589 more incidents. “But these results must be viewed with caution because they are based on just 12 cities for which we were able to obtain domestic violence data,” the report stated.

A previous CCJ report documented an 8.1% increase in domestic violence incidents in the spring of 2020 after cities implemented lockdowns to curb the spread of the coronavirus.

Criminologists, police, street outreach workers, professors and others have offered differing reasons for the historic increase in homicides.

The CCJ formed a group of professionals from various institutions to study different potential causes of the spike in crime, including “de-policing,” “de-legitimizing,” and escalating rates of gun purchases.

The report’s main takeaway was that, “As the pandemic subsides, long-lasting reductions in violence and crime will require pursuing evidence-based crime-control strategies and enacting long-needed reforms to policing.”

The CCJ report is just a snapshot. It did not include some major cities like New York City and Houston because of “the unavailability of data.” (New York City posts its homicide figures online, and for the first six months of 2021 the city had 21 more homicides than the same period in 2020, an increase of 10.9 percent.)

Richard Rosenfeld, a professor of criminology and criminal justice, and Ernesto Lopez, a research specialist, wrote the study, which included 29 cities such as Los Angeles, Norfolk, Virginia, Chicago, Seattle and Nashville, Tennessee.

Every one of the thousands of police agencies across the country is responsible for their own data, but they are not required to report their data to the FBI, which puts the material together in an annual report it releases the fall of each following year.

So far this year, less than half of all agencies have reported data to the FBI. It’s not immediately clear how much, if at all, homicides increased in smaller cities or small towns across the country, or how 2021’s national homicide total compares to 2020.

“Not surprisingly, the recent increases in homicide and some other violent crimes have stirred the greatest public concern, although their rates remain well below the historical peaks seen in the early 1990s,” the report concluded. “A precipitous rise in homicide in the late spring of 2020 coincided with the emergence of mass protests after George Floyd was murdered in Minneapolis, although the connection, if any, between the social unrest and heightened violence remains uncertain.”