Hundreds of people gathered in front of the White House and marched to protest the recent police-involved shootings in Minnesota and Louisiana. (Mahnaz Rezaie/The Washington Post)

It has become a sadly familiar ritual: protesters gathering on the streets of the District to vent their rage at yet another police shooting.

But as hundreds of sign-carrying, chanting marchers streamed from the White House to the Capitol, there was a different tenor to their frustration. The fatal shootings of Alton Sterling in Louisiana and Philando Castile in Minnesota — coming on consecutive days this week — provided an extra layer of desolation.

Many marchers said they had difficulty sleeping or had trudged through their workday after watching video of the aftermath of the Castile shooting Wednesday night, which came even as the nation was still processing the shooting of Sterling in Baton Rouge on Tuesday.

The video was the first thing Chris Jackson, 32, of Hyattsville, Md., saw Wednesday morning.

“It just bothered me all day long,” said Jackson, who works for the government and woke up at 5 a.m. “I talked to co-workers, I talked to a lot of people that were just distraught.”

People rally outside the White House over protest about police brutality in Washington. (Paul Holston/AP)

“It was not a productive day today because you can’t work,” he added. “You can’t see something like that over again and it not affect you. If it doesn’t affect you, that’s a bigger problem.”

At first, when Lindsey Vance, 31, checked her social-media account and saw the video, she thought what she had seen was connected to Louisiana. But she quickly realized it was another city and another black man.

Vance, a law student who lives with her family in Montgomery County, Md., said she cried while bathing her 15-month-old son.

“I started to think about how his life isn’t valued in society as much as it should be and it’s not protected,” she said. “I became overwhelmed with emotions and fear for my son. And then later in the day, when I heard about this protest, I chose courage instead of fear.”

Vance, who attended the rally with her son, said she thought it was important to set an example for him “that although scary things happen and there is injustice, there are still many good people in the world who are fighting to make it better for him and his future.”

Lawmakers were still inside the Capitol when the protesters arrived, filling the West Lawn of the Capitol. At one point, a group of House lawmakers emerged from the building to address the crowd.

Among those speakers was civil rights icon Rep. John Lewis (D-Ga.), who later joined the protesters for a short distance as they marched back toward the White House.

Protesters gather outside the White House in Washington Thursday. (Paul J. Richards/AFP/Getty Images)

“I was very impressed with the number of young people here. It was very moving,” Lewis said outside the Capitol. He said he had watched the videos, and he called the shooting of Castile “an execution, really,” that “should never, ever happen in America.”

Lewis added that the protesters are “very concerned about what is happening, and they should be. . . . People are saying, ‘It could have been my brother, or my son, or my nephew.’ It’s a human reaction.”

Rep. Hank Johnson, also a Democrat from Georgia, joined the protest and chanted with marchers late Thursday evening. The 61-year-old said he wanted to show his solidarity with the young marchers.

“All of us are frustrated; we are angry,” he said. “We know that something has to be done — we’re doing our best in Congress.”

“What we need to be about are civil liberties for African Americans, equal rights under the law, no extrajudicial killings of our young black men and women at the hands of rogue police officers,” he said. “We’re all tired of it.”