Homicides in the District rose for the third consecutive year in 2020, reaching nearly 200 for the first time since the previous decade and further stressing a city rattled by the pandemic and social and political unrest.

The number of killings stood at 198 Thursday evening, making the past year the deadliest in the city since 2004. More than 920 people were shot in D.C. in 2020, a 64 percent increase from three years ago.

The victims of deadly violence include a beloved school bus driver, a construction worker killed while renovating a home and a grandmother who survived covid-19. A little boy was fatally shot at a “stop the violence” cookout, and a toddler was killed by gunfire as he was strapped in a car seat.

“It breaks my heart when I think of the promises not fulfilled as a result of violence,” said the District’s newly named police chief, Robert J. Contee III, who starts Saturday. He takes over from Peter Newsham, who left to take over a police department in Virginia amid calls for quicker and broader changes to policing during this period of social reckoning.

The nation’s capital, like many other cities across the country, has experienced a spike in shootings and killings over the past year. The disruption of the pandemic may be partly to blame, experts say, but Contee and others also note that slayings in the District have been rising in recent years.

Contee, a native Washingtonian who has served on the District’s police force for 31 years, faces a complicated task of reducing crime as lawmakers and community members push to overhaul law enforcement.

The new chief, who must be confirmed by the D.C. Council, promised that officers “will be relentless in pursuit of criminals who make our communities unsafe.” He also promised he will be mindful of residents’ challenges and concerns, starting with “community conversation and agreement.”

“We will focus on guns, we will focus on violent crime,” Contee said, noting repeat violent offenders need to be held accountable “to stabilize communities in crisis.” He said, “All those things are important. But it’s also how we do it, and making sure we have a partnership in doing it.”

The District’s force is among several that will experience a change in leadership as many localities try to make policing more just and invest in programs that emphasize a public health approach to fighting crime. Police chiefs in several cities and in the Washington region retired or resigned in a year marked by demonstrations over what public safety should look like.

Troy Donte Prestwood, who chairs an Advisory Neighborhood Commission in one of the District’s more troubled neighborhoods in Anacostia, said that back in the high-crime era of the ’90s, people were “leaving the city because they were scared for their safety.” Now, he said, “I’m beginning to hear that conversation come up again in communities like mine.”

Prestwood said the new police chief “will be a great opportunity for us to reset, to think differently about public safety, and how public safety should look in communities of color.” He said he supports police and violence interrupters, who come into communities to help defuse conflicts, “but it’s not enough.”

In the greater Washington region, some other areas also experienced an increase in deadly violence in 2020 while homicides remained relatively steady in some jurisdictions. Homicides in the Maryland suburbs rose from 2019 to 2020, going up slightly in Montgomery County and up nearly 30 percent in Prince George’s County. Homicides in Northern Virginia went down slightly in 2020, compared with 2019, led by Prince William County, which had seven killings last year, compared with 15 the year before.

Police and experts who study crime patterns cite myriad possible reasons for the spike in killings and shootings in the District and some other cities. They point to the coronavirus crisis, which slowed arrests and complicated efforts to mediate disputes on the streets before they turned violent. Many people struggled with the stress of job loss and, with schools and community programs shuttered or moved online, safety nets were limited for young people.

Added to that were months of demonstrations in D.C. and across the country against police brutality, sparked by the killing of George Floyd in police custody in Minneapolis.

Both Contee and Newsham said D.C.’s homicide rate has been driven by an increase in gun violence. Police cite the rise in shootings and said the number of homicides from guns increased each of the past three years. In 2020, 87 percent of the killings were committed with a firearm.

Violent crime overall dropped 4 percent in the District in 2020, largely because the number of robberies has decreased.

The number of homicides in 2020 is far below the 482 recorded in the District in 1991, when the city earned the dubious reputation as the nation’s murder capital, but far exceeds the half-century low of 88 in 2012. There were 166 homicides in D.C. in 2019.

Most victims of deadly violence in 2020 were Black males. Twenty-six were women, and nine were homeless. The youngest was an 11-month-old girl who was injured while living at a homeless shelter; the oldest an 81-year-old man.

In a few instances, the victim was injured or killed in a prior year and the case was declared a homicide in 2020. Some fatal shootings were ruled justified and not included in the police count.

Detectives made arrests in more than half of the killings in 2020.

“It’s like we’re in the middle of a hurricane,” said Chuck Wexler, the executive director of the D.C.-based Police Executive Research Forum, which advises law enforcement agencies on best practices. “These homicide figures worry me. . . . Covid. George Floyd. Demonstrations. Riots.”

A survey of 223 police agencies by Wexler’s group and the Major City Chiefs Association found that homicides rose more than 28 percent in the first nine months of the year. Cities that experienced civic unrest had some of the highest spikes, including Minneapolis, Louisville, and Portland, Ore.

Other cities are showing similar trends, with both homicides and shootings up. Killings in New York rose 39 percent, while shootings more than doubled. Atlanta, Philadelphia, Los Angeles and Boston, among others, saw increases.

There are still many questions, Wexler said, as to whether 2020 is the start of a new norm or an aberration. He said police are stressed and tired from demonstrations, and pulling them from neighborhoods to handle protests has in some cases drained resources. He said he worries other changes, such as diverting money from police, are happening too fast.

“This whole issue of replacing the police with other social service agencies — it might come to be a good idea, but right now, it’s not really being thought through,” Wexler said, referring broadly to debates across the country. “It’s about cutting police budgets, but there is no direct link to what will replace what police are doing.”

In the District, the D.C. Council stripped $15 million from the $500 million police budget, which authorities say will reduce the size of the 3,700-member department. The council also approved measures to increase accountability and transparency, and codified prohibitions on tactics such as chokeholds.

Newsham, who along with Mayor Muriel E. Bowser (D) had opposed the cuts to the police budget, has long said one key to stopping violence would be a tougher stance on repeat violent offenders. He often railed against the justice system, saying it failed to take gun offenders seriously.

The December day after 15-month-old Carmelo Duncan was fatally shot in the car seat of his father’s vehicle, Newsham succinctly responded to a question about the root cause of violence: “There are too many illegal firearms in the District of Columbia.”

Many members of the council say they do not believe adding more officers is the solution to curbing crime, and want different approaches, such as expanding the violence interrupter program and finding alternatives to using police on certain calls, such as responding to people with mental illness who are in distress.

Charles Allen (D-Ward 6), who heads the public safety committee and is a leading voice promoting alternative justice programs, noted Contee has a long and respected career but said he wants to hear “where the chief plans” to take the department. “It can’t be enough to talk about reforms that were made in the past,” he said. “It’s got to be forward-facing, future-facing leadership.”

Allen said he sees “a clear role for law enforcement,” but he also called for “significant change” about “what is the future of policing and how we define public safety.” That definition, he said, must include “how you break cycles of poverty, cycles of violence. We have neighborhoods who feel they live in a constant state of lockdown, pandemic or not.”

The District is hiring a gun violence prevention director, who will work at the city administrator’s office in an attempt to tie other agencies into the crime fight. “We can’t talk about gun violence and not talk about housing,” Allen said. “We can’t talk about gun violence and not talk about mental health. We can’t talk about gun violence and not talk about failures of our education system. We have to have somebody who can see the big picture.”

But hammering out the specifics will not be easy, with varying views from law enforcement, community members and activists, including those on a commission formed to reimagine policing in the city.

The union representing the District’s police has blamed the D.C. Council for some of the rise in violence, singling out Allen. One effort police have opposed allows inmates who committed crimes before they turned 25 to petition for early release after serving 15 years of their sentences.

The police department, under Newsham, tweeted the bill, which passed the Council, would “provide for the early release of hundreds of violent gun offenders.” The union tweeted that Allen “has sent us back two decades in reducing homicides.”

Allen declined this week to respond to the criticism, though at the time he tweeted a pilot version of the early-release program did not result in a single case of recidivism, and he urged the police to stop “fearmongering.”

John Ayala, whose 11-year-old grandson Davon McNeal was fatally shot by a stray bullet police said was fired by members of a street crew at a Fourth of July “stop the violence” cookout, said he wants more, but smarter, police on the streets.

“We need police not just in their cars, but on foot patrol,” Ayala said. “They need to engage the community, not just ride past people.”

Ayala has emerged as an anti-violence advocate and this month led a vigil for slain toddler Carmelo. Ayala said he would like to see a return to the style of Newsham’s predecessor, Cathy L. Lanier, who spent years building community contacts and supporters. “It will get people to start reporting crime more,” he said.

“If we defund the police, we’re going to have fewer officers in the community than we do right now,” Ayala said. “The officers feel the Council doesn’t believe in them. Because of that, their attitudes are not where they should be when it comes to policing.”

The family visits Davon’s grave every day, and relatives pitched in to buy two vans donated to community groups needing transportation. The sides are adorned with faces of Davon dressed in his football uniform, and a message to the District: “Everyone deserves a chance to make it.”

Katie Mettler contributed to this report.

Correction: An earlier version of a headline on this story said D.C. had reached the highest number of homicides in 15 years. It has been the highest number in 16 years.