Washington’s 99th homicide came Friday when a 63-year-old woman, a beloved aunt and neighbor, was shot in the head in front of her home in broad daylight. The suspect is a relative who allegedly fired at responding officers and holed up in a nearby house for more than a day.

He was identified as Roosevelt Robinson, 67, of Northeast. Police said he was charged with second-degree murder while armed in the death of Loretta Carswell.

Within 18 hours, the city passed a grim milestone: Two more people were killed before sunrise Saturday in unrelated shootings, pushing the city’s year-to-date homicide count into triple digits. Homicide No. 100 came at 2:51 a.m. and No. 101 was six minutes later, at 2:57 a.m.

Three others were wounded in shootings, including a man who was struck by gunfire while riding a city bus.

The number of killings up to late August is four fewer than the total for all of last year. At the current rate, the number of homicides is likely to surpass last year’s total of 105 well before year’s end.

The 101 homicides signal the degree to which violence in the city has increased this year, just as it has elsewhere. The number represents a challenge to the District’s effort to curb the killings.

“As our city and area communities are experiencing increased acts of violence, it is the hopes of the PSA 602 Team that this recent surge in disorder and heartache comes to a quick end,” city police wrote Friday on an online bulletin board. PSA stands for police service area.

Police urged residents to provide information to help solve the crimes.

On Friday about 10:15 a.m., shots were fired in front of the home of Carswell, who lived in the 3700 block of 18th Street NE, a street of rowhouses with neat lawns in Brookland. Carswell was found dead in front of her home.

When officers arrived, a man began firing from the front porch of a nearby house, forcing them to take cover, police said.

Carswell’s brother, Darrell Carswell, identified the man as a relative who had been living in a home owned by the Carswell family in the 3600 block of 18th Street NE. It was at the family home that the man held police at bay for more than a day while officers blocked streets and marked off the neighborhood with yellow caution tape.

But on Saturday, while police urged the man to come out, life went on within the taped perimeter: A child bounced a basketball down the sidewalk, and others played basketball and tennis at the nearby Taft Recreational Center. A man pushed a baby in a stroller.

Neighbors told a reporter that their biggest problems are with loitering and car break-ins. The shooting was a shock to Brookland, a neighborhood that was the among the first to gentrify in Northeast.

In the meantime, relatives gathered at the home of a family friend in the neighborhood to recall the slain woman and to watch over the family home where the man was barricaded.

They looked on from a distance as police, armed with shields and a battering ram, forced their way into the house about 5 p.m. Saturday. Not long after, the man was taken out in handcuffs, prompting shrieks and cries.

In a statement, D.C. Police Chief Cathy L. Lanier praised the police Emergency Response Team for “an outstanding job” in protecting the life of the suspect and the lives of neighborhood residents.

Carswell’s brother wept as he watched police escorting the suspect. He said his sister was known for her generosity. She had cared for foster children and a niece and nephew, and she raised two children of her own.

“My sister was the most wonderful person in the world,” Darrell Carswell said. “It’s something I never imagined would happen to me, and especially not to my sister, who never did anything wrong.”

Carswell had been a Metrobus driver for many years, retiring two years ago. Delores Proctor, director of Metro’s bus service, called her a “wonderful employee and a wonderful person” whose passengers “loved her.”

In retirement, relatives said, she doted on grandnieces and grandnephews, showering them with toys and clothes. And she traveled to Mexico and Jamaica.

“If you ever need anything, she would be able to supply that for you — somewhere to stay, food, clothes on your back, anything like that,” said her nephew Darius Carswell.

Meanwhile, a man was shot in the 2300 block of Pitts Place SE at 9:15 p.m. Friday. About 10:30 p.m., someone fired at a Metrobus in the 2400 block of Elvans Road SE. A wounded passenger ran from the bus and was found nearby with ­“non-life-threatening injuries,” Metro spokesman Dan Stessel said. Stessel said police do not think the victim was the target.

Another man was hit by gunfire at 13 minutes past midnight at Florida Avenue and Orren Street in Northeast. All three survived.

But by sunrise, two other men would be dead. Police who went to the 1300 block of Stevens Road SE, where shots were reported at 2:51 a.m., found Antonio Dean, 24, dead with gunshot wounds. A few minutes later, police were sent to the 300 block of 54th Street NE, where Kenneth Earl Watson Jr., 26, was found with fatal gunshot wounds.

Martin Weil and Clarence Williams contributed to this report