CNN  — 

Last year saw the highest number of law enforcement officers who were intentionally killed in the line of duty since the terrorist attacks of Sept. 11, 2001, an increase that comes as a rise in gun violence and homicides continues across the country.

According to preliminary year-end data provided to CNN by the FBI, 73 officers died in felonious killings in the line of duty in 2021. The year marks the highest total recorded by the agency since 1995, excluding the 9/11 attacks.

Gunfire has consistently been the leading cause of felonious officer deaths each year – and 2021 was no different. The FBI has not released its full end-of-year breakdown but reported that 55 officers were killed by gunfire in 2021 through the end of November, up from 39 in the same time frame in both 2020 and 2019.

Homicides rose in 2020, a year marked by a global pandemic and the murder of George Floyd by a Minneapolis police officer and subsequent unrest. In its 2020 UCR report, the FBI noted that an increasing number of homicides were committed with a gun. For many cities, the elevated rates of homicide continued into 2021.

More than two-thirds of the country’s 40 most populous cities saw more homicides last year than in 2020, according to a CNN analysis of police department data, and 10 of those cities recorded more homicides in 2021 than any other year on record.

“When homicides go up, more shootings go up, and it contributes to an overall increase in violence and police officers find themselves in the middle of that environment,” said Chuck Wexler, the executive director of the Police Executive Research Forum (PERF).

Covid-19 still the leading cause of officer deaths

Maria Haberfeld, chair of the Department of Law, Police Sciences, and Criminal Justice Administration at John Jay College, who has analyzed data on police deaths in the line of duty, says that a rise in violence against police officers is a phenomenon that happens “every few years” because of an event that serves as a catalyst.

Typically, she said, the uptick is tied to a high-profile case in which an officer or department is accused of misconduct and then that “spills over to all the other police officers around the country.”

The 73 felonious deaths reported by the FBI are a 59% increase from 2020’s total of 46, breaking the previous high of 72 felonious killings in 2011. According to the FBI, at least eight police officers also lost their lives in premeditated, ambush-style attacks last year.

The FBI classifies a death as a “felonious killing” when an officer is “fatally injured as a direct result of a willful and intentional act by an offender.” Separately, 56 officers were killed accidentally while in the line of duty last year, up from 46 in 2020.

Felonious killings were not the No. 1 cause of death for law enforcement officers in 2021: For the second year in a row, that was Covid-19. According to the Officer Down Memorial Page, a non-profit dedicated to memorializing fallen officers, the total number of officers who died in the line of duty in 2021 was the highest on record, driven by Covid-19. The group reported 336 Covid-19 deaths among line-of-duty officers in 2021, a 32% increase from the 254 officers who died from Covid-19 in 2020.

“As tragic as this is to see this increase in felonious assaults against police officers, more officers will die of Covid than will be stabbed, shot, or die in traffic accidents and many of those deaths are preventable,” said Wexler of PERF, a national police research and policy organization that advises police leaders on best practices.