He was old enough to dance to a good beat but too young to know his favorite color.

Carmelo Duncan was 15 months old when he was fatally shot Wednesday night in Southeast Washington as he was strapped in a car seat in the back of a vehicle driven by his father.

Police said it appears that at least two people opened fire as the car moved along Southern Avenue, striking it as many as 10 times. Carmelo was hit several times, including in the head, police said, and he died at a hospital.

“He was the best baby ever,” said his 28-year-old mother, Taquana Duncan.

Carmelo’s 8-year-old brother was next to him when bullets hit the car and shattered windows shortly after 9:30 p.m. Police said they found evidence that more than one gun was used and added that they think the assailants targeted the vehicle, but they don’t know why.

Dozens of mourners gathered Thursday night in the block where Carmelo was killed. They offered prayers for his family and for other families that have lost loved ones to gun violence, the coronavirus and social ills. They also demanded an end to such violent attacks and called for witnesses to come forward to bring justice for Carmelo’s death.

“Somebody knows something! Somebody knows something!” the crowd shouted as they began a march along Southern Avenue.

The toddler is among the youngest homicide victims in the District in 2020 and the youngest to be fatally shot in a year when gunfire has pushed the number of killings to 187, the highest in the nation’s capital in 15 years.

Davon McNeal, 11, was killed by gunfire at a Fourth of July “stop the violence” cookout, and Malachi Lukes, 13, was shot walking with friends to play basketball. Police said toddlers ages 11 months and 2 years were fatally beaten in child abuse cases in February and April.

“There are simply no words at the sense of outrage we all feel,” Mayor Muriel E. Bowser (D) said at a news conference Thursday, adding, “We’re all sick for the heinous crimes in our city” and for “the havoc and pain that guns are causing in our city.”

Other cities across the country have seen similar spikes in homicides and shootings, including New York City and St. Louis, where homicides are up about 37 percent this year, and Philadelphia, where they’ve jumped nearly 40 percent. Similarly, there has been a 42 percent increase in Atlanta. Officials have cited stresses related to the pandemic and strained relationships between police and the communities they patrol as some reasons for the rise in violence.

No arrests had been made as of Thursday afternoon in Carmelo’s killing. The FBI and ATF are assisting in the investigation, and have added to a reward offered by the city, bringing it to $60,000. Authorities were searching for a dark gray SUV with tinted windows seen speeding away from the shooting scene along Southern Avenue, near Central Avenue on the border with Maryland.

The shooting occurred in the Marshall Heights neighborhood, a wedge-shaped community roughly bounded by Southern Avenue, E. Capitol Street and Benning Road. There have been 13 homicides on those blocks this year, eight of them with firearms.

Carmelo was killed on a well-traveled thoroughfare on a hilly slope that passes newer-model three-story duplexes with front yards, leading down to Central Avenue, where there is a church and a small shopping plaza.

Delia Houseal, chairwoman of the Advisory Neighborhood Commission in Marshall Heights, said “there has been a lot of shootings in our area for the past couple of days now.” She said the gunshots that struck Carmelo woke her up.

Houseal blames the violence on disruptions caused by the coronavirus — people home, out of work, out of money and out of options. “These are survival crimes associated with people who are traumatized,” she said. “There are lot of people who are struggling and they need support. . . . Lately, a lot of people have been acting out of desperation.”

In September, the Washington Business Journal named Marshall Heights one of the region’s hottest spots for home sales, noting its mix of single-family dwellings and townhouses selling for about half of what similar properties elsewhere are going for.

Houseal said the neighborhood is a great place to live, but cautioned, “I do feel less safe over the past couple of months.”

On Thursday, Carmelo’s family struggled to understand what had happened. Taquana Duncan, who works as a private security guard, said only a few words about her son’s death before ending a short conversation in tears.

The family provided a photo of Carmelo standing on a small table, his tiny mouth agape, decked out in stylish clothes — a tie-dye shirt, stonewashed jeans and baby Air Jordan sneakers. He wore a pendant around his neck with a picture of his younger self, a gift from an aunt. In addition to his brother, Carmelo has a 6-year-0ld sister.

At just over 1 year old, relatives said he was already chasing the family dog, a Yorkshire poodle named King, around his house in Southeast Washington.

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His maternal grandmother, Tiara Duncan, 44, said Carmelo enjoyed his newfound freedom of walking and running, and liked to dance to any type of music, as long at it had a good beat. She described him as an “energetic” child who seemed perpetually happy and “always had everyone smiling.”

Tiara Duncan said Carmelo was with his father Wednesday night as he drove to a house on Southern Avenue to pick up his 8-year-son. She said they had just left there when the shooting occurred.

The grandmother said she had one message for the District’s mayor and police chief: “Take the guns off the street.”

It is a message D.C. Police Chief Peter Newsham agrees with. He has made targeting illegal firearms a central part of his crime plan, and when asked Thursday for the root cause of violence in the District, he answered simply: “There are too many illegal firearms in the District of Columbia.”

Newsham, who is leaving the D.C. police over the next several weeks to lead the department in Prince William County, Va., expressed frustration over the mounting killings as he ends his 31-year career with the D.C. force, the last three as chief. He has repeatedly spoken out against a criminal justice system that he says takes gun crimes too lightly and allows offenders back on to the streets without sufficient punishment.

At the news conference with the mayor, he noted a picture of Carmelo on the police reward poster, his smiling face bundled in a winter coat, and said, “You look at the picture of that little child, that baby, he had his whole life ahead of him.”

Newsham pleaded with anyone with information to come forward and help police, especially if any of the homes or businesses along Southern Avenue have surveillance video. He said investigators are working with the father for any help he can provide.

“He just lost an infant child,” the chief said, adding “we want take our time, and try to help the family as best we can.” He added, “I am sure the dad and mom want to ensure the people that were responsible for this are held accountable.”

He said evidence that more than one gun was used suggests “that at least the vehicle was a target, and this was not random.”

Moments after the shooting, the toddler’s father stopped near Central Avenue. Firefighters and medics with Engine 30 and Medic 30 were on a call just up the street, treating a patient for an allergic reaction, when they heard the gunshots and rushed to help.

“They responded heroically,” Newsham said. “They got that kid to the hospital as quickly as they could, and unfortunately, the result was not one that any of us wanted.”

On Thursday evening, Ricardo Scott, the radio personality known as D.J. Rico, led dozens of marchers along Southern Avenue, urging neighbors to leave their homes during the vigil and for witnesses to come forward.

“You can come out of your house to get an outfit, or to go get some crab legs. Why can’t you get out of your house and show love and support to this family?” Scott said.

Before the march began, activist Jawanna Hardy carefully encircled stuff animals around a utility pole and paused to stare at a photo of Carmelo laughing before she continued to build her memorial on the block where he was fatally shot.

As Hardy worked, Wanda Ayala tearfully watched the placement of each toy and the pain of her own loss streamed from her eyes as she cried behind a mask dedicated to the memory of her grandson Davon, who was killed July 4.

“Oh my God,” Ayala sobbed.

She cried out.

Within moments, the two women hugged tightly as Ayala cried not just for her loss, but for the pain of Carmelo’s mother, grandmother and family. The pair encouraged each other in their fight to end such tragedy on city streets.

“It’s just got to stop,” Hardy said.

“They’re taking our babies,” Ayala offered. “I feel like I lost a grandchild. It’s not right.”

“We have to get these guns off the street,” Hardy said.

“We can’t keep this up,” Ayala said. “We as a community have to put a stop to it.”

Fenit Nirappil and Julie Tate contributed to this report.