D.C. police arrested a suspect in the fatal shooting of a 6-year-old girl in Southeast Washington and said they are investigating whether the late-night burst of gunfire was linked to a suspected drug crew authorities say has terrorized the neighborhood with unrelenting violence.

Nyiah Courtney’s parents were both wounded in the July 16 shooting in Congress Heights, along with three others. Police said her father is a suspected member of the crew and may have been targeted.

Police arrested the wounded father the next day as part of an indictment filed against more than a dozen people facing federal drug and firearms charges. Court papers described them as affiliated with the MLK Crew, named after the street where they are allegedly based, and on which Nyiah was fatally wounded: Martin Luther King Jr. Avenue SE.

“The prayers of the community have been answered,” D.C. Police Chief Robert J. Contee III said at a news conference Wednesday, recalling a child remembered for her energy and enthusiasm, who had braided her hair to look like her grandmother.

“I’m here to announce today that we got our man,” Contee said.

Marktwan Hargraves, 22, was charged with murder. Authorities said he is from Maryland; court documents also show an address in the District.

Nyiah’s grandmother, Andrea Courtney, said she was happy a suspect had been arrested but she did not believe the police account that her granddaughter’s father, 31-year-old Nico Griffin, might have been targeted or was involved in a drug crew.

“He’s not that type of person,” Courtney said, adding the family is working on funeral arrangements and feels overwhelmed by the death and the allegations. In a court hearing, Griffin told a judge he worked as a welder. His attorney in the federal case declined to comment on the case when reached Tuesday; he could not be reached Wednesday.

Nyiah’s death, a shooting outside Nationals Park a day later that forced a game to be postponed, and more gunshots fired on 14th Street that sent outdoor diners scattering in the Logan Circle area have brought urgent and widespread attention to gun violence in the District.

Homicides are up over last year and shootings, while dropping slightly in recent weeks, have spiked since 2019, raising concern among residents and city leaders.

At Wednesday’s news conference, Mayor Muriel E. Bowser (D) and other officials spent nearly 90 minutes explaining various police and alternative justice programs to address violence. She repeated demands that agencies other than police step up to help and said delays from a large backlog of criminal court cases put on hold during the pandemic are hampering justice.

Bowser also said she will ask the D.C. Council to spend an additional $11 million to hire 20 police officers in the next few months and 150 officers in fiscal year 2022. That would bolster a force depleted by a growing number of retirements and resignations, and a freeze on hiring the administration blames on a $15 million budget cut imposed by the D.C. Council last year.

Even as the officials spoke, another person was killed in a shooting in Southeast Washington, about one mile from where Nyiah had been fatally injured. There was no immediate indication there was a connection.

The July 16 gunshots that killed Nyiah were fired about 11:10 p.m. from a passing Saturn Ion that police said they later found abandoned and burned in Northeast Washington.

The death of the little girl, who had dreamed of becoming a dancer and couldn’t wait to start first grade this fall, reverberated across the District.

A day after the shooting, a visibly angry Contee held up a picture of Nyiah and demanded television viewers look at her face and help find her killer. Federal authorities joined in the investigation. And Bowser authorized police to spend as much on overtime as they needed, telling lawmakers that residents tell her “they do not feel safe while the threat of gun violence looms.”

A little more than a week later, Contee told reporters he had kept his promise with the arrest.

Police initially said Hargraves was charged with first-degree murder while armed but later Wednesday said the charge was second-degree murder while armed. The reason for the discrepancy was not immediately clear. It could not immediately be determined whether Hargraves has an attorney in the murder case. Attempts to reach his relatives were not successful.

At the time Nyiah was killed, Hargraves was free awaiting trial in Maryland on charges including motor vehicle theft and illegal possession of a handgun stemming from an arrest in summer 2020.

His attorney in that case, Richard A. Finci, said the case, scheduled for trial in October, had been delayed because of the pandemic. “This is shocking to me,” he said of the murder charge. “He’s a good client. He listens to what I have to say. He’s respectful, and he does not have much of a criminal record.”

Contee said the drug investigation began when the threat of gun violence attracted investigators to the streets around the strip of liquor stores, carryouts and convenience stores that largely define the 2900 block of Martin Luther King Jr. Ave. SE. Starting in January, undercover D.C. police and FBI agents began to document what they say were prolific sales of illegal drugs, accompanied by firearms and gunfire.

“The MLK Crew has essentially taken over the block and the surrounding area and is distributing narcotics on a daily basis,” Assistant U.S. Attorney David T. Henek wrote in court documents in the arrest of one of the suspects tied to the group. “The MLK’s presence has contributed to unprecedented violence in the area, including several recent shootings.”

The indictment charging alleged members of the MLK Crew was unsealed Wednesday in U.S. District Court, identifying 11 of 13 people charged. Nyiah’s father, Griffin, is among them. A 12th person was arrested in another jurisdiction, police said, and the final suspect is being sought.

Contee said 13 firearms were confiscated during the investigation, in addition to money and drugs including crack cocaine, PCP, fentanyl and marijuana. He said a man who was shot and critically wounded the day before Nyiah was killed is also charged in the indictment.

At least four additional people allegedly linked to the crew have also been arrested, Contee said, telling reporters more suspects could be charged. He directed some of his remarks at alleged crew members, warning, “We got your guns. We got your drugs, we’ve taken your cars, and we got your friends. And now we’re coming for you.”

Authorities said Nyiah’s father and at least one other person linked to the crew were on the street when the July 16 shooting occurred. Contee said it is possible that members of that crew were targeted, adding that a definitive motive would have to come from the shooter.

The indictments targeting the purported MLK Crew were issued July 14, police said, two days before Nyiah was shot, and warrants were delivered to police July 19, the day most of the arrests were made.

Nyiah’s father, however, was arrested the day after his daughter was shot, in a park near the crime scene. Police at the time said only that he was wanted on a warrant “in a sealed indictment.”

Police said he had bullets in a pocket and was charged in Superior Court with possession of unregistered ammunition. He appeared in court in a wheelchair, his right leg bandaged, and was then taken into federal custody.