Law enforcement agencies across the country are struggling to replace police officers who have left the force or have retired since the rise of anti-police and “defund the police” marches, according to new research conducted by the Police Executive Research Forum.

There is “a crisis on the horizon for police chiefs when they look at the resources they need, especially during a period when we’re seeing an increase in murders and shootings,” Chuck Wexler, the head of the forum, told the Associated Press.

The marches, which started after George Floyd was killed by a police officer in Minnesota last year, have caused some departments to see a 45% increase in retirements, according to the research.

On average, the nearly 200 law enforcement agencies that participated in the research say their hiring has slowed by 5%.

“It’s a wake-up call,” Wexler added. The marches have also caused a shift in priorities for police departments, according to Atlanta Police Chief Rodney Bryant.

“Days of old, you wanted someone who actually had the strength to be more physical,” Bryant said, noting that is no longer “what we’re looking for.”

Now, police departments are “looking for someone who can actually relate to the community but also think like the community thinks.”

Lynda R. Williams, president of the National Organization of Black Law Enforcement Executives, said the new trend presents a unique challenge to hire someone from a community that hates law enforcement.

“It’s hard to recruit the very people who see police as an opposition,” she said.

Police departments are also battling rising crime rates.

In New York City, crime spiked 22% in May compared to the previous year.

This overall rate was driven by a 46.7% increase in robbery, a 35.6% increase in grand larceny, a 20.5% increase in felony assaults, and a 73% increase in shooting incidents.

Wexler’s organization, which represents a fraction of the more than 18,000 law enforcement agencies across the country and is not necessarily representative of all agencies, examined the resignations and hiring practices of 194 police departments.