The suspected shooter was identified as 31-year-old Cole Allen of Torrance, California, ABC News confirmed. He is in custody.
The incident sparked chaos inside the ballroom before Allen was subdued by law enforcement.
FBI swarms suspect's Torrance home
Eyewitness News crews on the ground watched as FBI agents arrived outside of the suspected gunman's residence on Gramercy Avenue in Torrance. There was a very large law enforcement scene in the residential neighborhood, including FBI agents in tactical gear and armored vehicles.
At one point, AIR7 video appeared to show occupants of the home speaking with federal agents on the front porch. Later, it appeared spotlights were focused on a second-story window and the front door.
Before agents arrived, ABC7 Reporter Kevin Ozebek was able to knock on the door where authorities believe Allen lives. No one answered, but a neighbor said he often sees Allen riding his moped in the neighborhood.
Eyewitness News video shows a large crowd of neighbors behind crime scene tape in the Torrance neighborhood.
"I walked the dog over here, and I got caught up in this circus of helicopters, media, and neighbors," said Erik Orrie, who lives nearby.
What we know about Cole Allen
According to a LinkedIn page connected to the suspect, Allen is a trained mechanical engineer who now works as a tutor.
His current employer, C2 Education, named Allen "Teacher of the Month" just last year, according to the LinkedIn page.
He describes himself on LinkedIn as a "Mechanical engineer and computer scientist by degree, independent game developer by experience, teacher by birth."
Investigators in Washington, D.C., say the motive in the shooting remains unknown. According to voter registration records, Allen is listed as "no party preference."
Law enforcement sources tell ABC News they have Allen's phone and are waiting on a judge to sign off on a search warrant so they can go through the devices.
Sources also say that, as of right now, it appears Allen went from Los Angeles to Chicago before traveling to Washington, D.C.
READ MORE: Trump safe, suspect in custody after shooting incident outside White House Correspondents Dinner
What happened at the White House Correspondents' Dinner?
President Donald Trump posted a video showing agents taking down the suspect, who he said "charged a security checkpoint armed with many weapons."
"He started running from 50 yards, and he was fast. He was like a blur on tape," Trump said of the suspect.
In another post on Truth Social, Trump shared photos of the alleged shooter face-down on the ground after being apprehended.
As agents engaged with the suspect, a chaotic scene unfolded inside the Washington Hilton hotel ballroom. Officers in tactical gear with long guns jumped over tables, brandishing their weapons as the president and other dignitaries, such as Vice President JD Vance, were rushed from the stage.
Attendees ducked under their tables.
"It is always shocking when something like this happens," Trump told reporters at a press briefing from the White House later Saturday night.
The shooting incident took place near the main magnetometer screening area at the White House Correspondents' Dinner, according to the Secret Service.
During the press briefing, Trump said that a Secret Service member was shot, but the bullet hit the agent's protective vest. The president said he spoke with the agent, and he was in good spirits.
"I told him we love him and respect him, and he's a very proud guy," he said.
Saturday was the first correspondents' dinner that Trump had attended as president. He was scheduled to speak.
The dinner was underway, and Trump, the first lady and other dignitaries were sitting at the main table and White House Correspondents' Association President Weijia Jiang was chatting with the dinner's host Oz Pearlman, when some attendees said they heard several loud bangs shortly after 8:30 p.m. ET.
In a social media post, Trump praised the Secret Service for their work.
"Quite an evening in D.C. Secret Service and Law Enforcement did a fantastic job. They acted quickly and bravely," he said.
In a later post, Trump said law enforcement requested attendees leave the premises and the dinner would be rescheduled within 30 days.
"We very much wanted to continue it, because I don't want to let these sick people, these thugs change the fabric of our lives, change what we do," Trump told reporters.
Jiang initially told the crowd at the Washington Hilton ballroom that the program would continue however, she later told the crowd that they had to leave.
"I said earlier tonight that journalism is a public service because when there is an emergency, we run to the crisis, not away from it," she told the crowd.
"And on a night when we are thinking about the freedoms in the First Amendment, we must also think about how fragile they are. I saw all of you reporting, and that's what we do," Jiang added.
ABC News contributed to this report.