Clarification: This story has been updated to clarify that 10 homicides this year involved known violent offenders who had been recently released from prison on charges related to previous slayings.

D.C. Police Chief Cathy L. Lanier comforts a grieving mother at the scene where her son was fatally shot Aug. 18, 2015, on the front lawn of St. Luke Roman Catholic Church on East Capitol Street Southeast in Washington. (J. Lawler Duggan/For The Washington Post)

The shootout occurred on a Tuesday morning in early August in a parking lot off Suitland Parkway in Southeast Washington. John A. Gassaway was struck by eight bullets fired into his lower body. Police said that as he fell, he raised his own gun and fired at his assailant, fleeing in a silver Kia Borrego.

Gassaway, 43, is a victim and a defendant in the same case — hospitalized for nearly three weeks while also under arrest, charged with assault with intent to kill.

This was not his first gun battle. He killed a man 21 years ago, a bystander at a cookout struck in the chest as bullets crisscrossed a courtyard on Savannah Terrace SE, a block from where Gassaway was shot.

As shootings and homicides mount across the District, officials including the police chief are focusing on repeat violent offenders, such as Gassaway, as principal contributors, reigniting a perennial debate in criminal justice circles over whether some violent offenders are getting out of prison too soon or are not being given long enough sentences.

Authorities contend that too many convicts are back on the streets by way of lenient sentences, probation, parole and a growing reliance on diversion programs designed to cull the prison population through alternatives to incarceration. But some criminologists and experts say it is too early to generalize about what has been the cause of the recent increase in violent crime in the District and other big cities nationwide.

Mayor Muriel E. Bowser (D) appeared at a town hall meeting in Washington Aug. 19, 2015, where residents expressed frustration at a recent sharp increase in violence. (WUSA9)

D.C. Police Chief Cathy L. Lanier says there are gaps in the system, and at an Aug. 3 meeting of the Major Cities Chiefs Association (MCCA), she called for a wide national review to ensure that only truly nonviolent offenders are eligible for diversion programs.

“We are seeing far too many of our repeat violent offenders out here being reckless with firearms over and over again,” Lanier said. At a news conference last week, she said, “There is a push to release a lot of people.”

Police said much of their evidence is anecdotal. Lanier has said that the 50 people who have the most gun convictions in the District racked up a total of 849 prior arrests. She also said that 10 homicides this year involved known violent offenders who had been recently released from prison on charges related to previous killings.

The chief has said the failings in the system could lie with police, prosecutors, judges or laws. It is essential, she said, to examine what suspects “are charged with and what they’re actually convicted of. Sometimes there’s a disconnect there.”

In 1994, a year that ended with four times the number of killings typically recorded now, Gassaway was charged with first-degree murder for shooting the bystander, assault with intent to kill for firing at his rival during the shootout and with various gun offenses. All told, Gassaway, then 22, faced life in prison.

But a jury saw the case differently. Gassaway, after confronting people who had beaten up his cousin, was shot at as he turned his back on the group. He grabbed his gun and fired back, and a bullet hit a man named Robert Edward Green.

The jury convicted Gassaway of manslaughter, rejecting the prosecution’s narrative that after being shot at, Gassaway ran a good distance to retrieve his gun and that by the time he returned, the threat had passed. Onlookers said that Gassaway had left his gun in the grass, that he quickly picked it up and that the gunshots from both sides were virtually simultaneous.

That nuance spared Gassaway a lifetime behind bars.

“The facts in your case show that you were not the initial aggressor, which is why I’m not locking you up for as long as I can,” D.C. Superior Court Judge Judith E. Retchin told Gassaway at his sentencing. The judge told Gassaway that she wanted him to have “a light at the end of the tunnel” so that when released, “you will not be taking another life.”

The concerns Lanier and other police chiefs are expressing are part of a national dialogue over prison populations that increased sharply during the war on drugs. The mantra had been, “Be tough on crime.” Now it is, “Be smart on crime.”

Marc Mauer, executive director of the Sentencing Project, an advocacy group for criminal justice reform, said the United States “has been locking up both violent offenders and nonviolent offenders at record rates for a number of decades. There is a growing consensus that we’re well past the point of diminishing returns for public safety.”

Mauer said the trend had been to “send more and more people to prison and keep them there for longer periods of time. . . . If getting tough was the way to solve the crime problem, we’d be the safest country in the world.”

But police officials say they are seeing more suspects with criminal records and are attributing a rise in homicides in more than two dozen cities across the country in part to repeat offenders. Homicides in the District are up about 35 percent this year.

“Our cities are dealing with a very small group of people who are committing the vast majority of the crimes in our communities,” said J. Thomas Manger, chief of the Montgomery County Police Department and head of the MCCA, which represents heads of law enforcement agencies across the country.

Manger, speaking after the Aug. 3 emergency crime summit in Washington that was called to address the rising violence, said his group backs ending mass incarceration practices, promoting reentry programs for prisoners and diversion initiatives to keep those charged with nonviolent offenses out of prison.

But Manger said those being released “are coming into a community without the skills they need” to avoid returning to crime. And he warned that nonviolent offenders need to be carefully screened.

“We have individuals we arrest for shoplifting or breaking into a car, but look at what they’ve been involved with in the past 10 or 15 years, and you find they’ve been arrested three times for armed robbery,” Manger said. “That is a repeat violent offender.”

Anita Alvarez, the state’s attorney for Cook County, Ill., which includes Chicago, said prosecutors support diversion programs “to get people out of the system who don’t need to be in the system.” But, she said, “at the same time, we can’t forget the violent criminal who is out there shooting up our streets or snuffing out the life of a 2-year-old.”

But the Sentencing Project’s Mauer said that those convicted of crimes have always been returning to communities and that he does not know of any increase. The District follows federal prison rules, and all those convicted of crimes serve at least 85 percent of their sentences before probation.

Mauer said he does not agree that repeat offenders are driving the sharp rise in crime. “Yes, there are some people who commit a disproportionate amount of crime,” he said. “But it’s always easier to figure out who they are, looking backward, and much more difficult to make that prediction looking forward.”

And although more arrestees may be diverted into community programs instead of being sent to jail or prison, Mauer said the number of people being released from behind bars on parole or probation has not changed in the past decade.

Alvarez cautioned that alternative programs offering alternatives to prison are “only going to work if the resources are there to get these people the drug treatment that they need, the mental-health treatment that they need.”

Gassaway, the man charged in the shootout near the Suitland Parkway on Aug. 5, got his break in 1994 from a jury that decided that he had committed manslaughter, not murder, and from a judge who agreed that he had returned fire and not instigated it.

Court records show that Gassaway was frustrated upon entering the now-closed Lorton prison. While his attorney sought a reduced sentence, calling Gassaway a man “who has skills, who has potential,” the defendant himself wrote to the trial judge saying that prison was no place to get help.

He wrote that instead of getting help, as the judge had wanted, “I basically sit around and play table top games and [watch] TV, not the things for my rehabilitation.”

In neat cursive writing, Gassaway said he would have liked to update the judge on his progress, “but there is no way for me to have anything to show you because there are no programs. . . . I feel like you sentenced me so that I be rehabilitated through programs that will help me better myself and return to society in a better way than I left.”