D.C. police arrested a suspect on Saturday in the death of 11-year-old Karon Brown, who was shot and killed last Thursday in Southeast.

Officers arrested 29-year-old Tony Antoine McClam of Southeast in the killing, and charged him with second degree murder while armed. On Monday, officials upgraded the charge to first degree murder while armed. McClam is accused of shooting into a vehicle where Brown was sitting, killing him. Police were looking for up to five people involved in the dispute that led to Brown’s death.

There is not yet a known motive in the case, Metropolitan Police Department Chief Peter Newsham said at a press conference on the arrest on Saturday.

Brown was allegedly killed after a dispute on the street in the 2700 block of Naylor Road, Southeast. Brown and his 12-year-old brother, Quentin, had walked to a McDonald’s near his Southeast home to get food for their older sister on Thursday evening, the Washington Post reports. Quentin lost patience and returned home, while Karon stayed. A fight involving children and adults broke out inside the restaurant and eventually spilled out onto the street, the outlet reports. Karon was apparently involved in the conflict. Quentin, who had returned just before 7 p.m. to get his brother, heard gunshots and ran home, per the Post.

A bystander who saw Karon in the scuffle picked him up off the street and placed him into his car, WUSA9 reported last week. A man fired a gun into the car and struck Brown. The bystander drove Brown to a Prince George’s County fire station, where he was driven by ambulance to a nearby hospital, police said last week. Lifesaving efforts at the hospital failed and Brown was pronounced dead.

Police released surveillance photos of a suspect in the shooting last week, whom they identified as a black male between 20 and 30 years old. Newsham said at the press conference Saturday that police are still investigating the case.

Court documents lay out McClam’s version of events, which he shared in an interview with detectives: McClam told police he shot Brown in self-defense. Days before Brown’s murder, a group of children had jumped McClam’s stepson in the park, leading to several more confrontations that week, he said. On Thursday, he, another adult male, and several children went to the McDonald’s parking lot to confront another group of children about the incidents. They surrounded Brown and one other child, and a fight broke out, per court documents.

As the fight continued, a silver car pulled up and the driver confronted McClam, he said. McClam claimed the driver said he was related to Brown, though police have no evidence that the two are related, court documents say. McClam said that he thought the driver was reaching for a weapon while leaning over in his seat, and he fired into the car because he feared for his life. Detectives say that, per surveillance videos that captured part of the incident, “there is no indication that the Defendant shot in self defense,” according to court documents.

Karon Brown was a recent graduate of Stanton Elementary School, also near the site of his killing. He was set to begin the sixth grade in a few weeks. He was killed nearly a year to the day after the murder of 10-year-old Makiyah Wilson, who had been friends with both Karon and Quentin, their mother told the Post.

“I still can’t believe it. I am waiting for someone to say all this did not just happen. This is not how we planned our summer. Now I have to sit here and plan a funeral for my baby,” she told the outlet. Brown’s family had lived near Wilson’s in Northeast, and their mother moved them away to try to escape the violence, per the outlet.

Community members will hold a vigil on Tuesday at the Stanton Elementary School field in honor of Karon Brown’s life. The vigil will go from 6 p.m. to 8 p.m.

Ninety-four people have been murdered in the District of Columbia so far this year, an 11 percent uptick from this time last year. On Sunday alone, seven people were shot in four separate incidents in the District. Police and the mayor point to illegal guns as a major cause of the violence, and urged the community to report people they know to be carrying illegal firearms.

“Guns do indeed kill people. Guns in the hands of the wrong people are deadly and make our neighborhoods unsafe,” Mayor Muriel Bowser said on Saturday. “We cannot wait for another child to fall victim to senseless gun violence. I’m calling on everyone in the District of Columbia who knows of anyone who has an illegal gun, or someone you know shouldn’t be having a gun, or you’re scared of somebody that you know in your neighborhood, community, or in your home, that has a gun. Please reach out to us for help. People who would be so brazen and callous have no regard for human life and no regard for the innocence of childhood, [and] cannot be allowed to carry a gun in our streets.”

This post has been updated with information about a vigil in honor of Karon Brown on Tuesday, as well as information about Tony McClam’s account of events based on charging documents.