CBS News has confirmed the gunman at the congressional baseball practice has been identified by law enforcement as James T. Hodgkinson, 66, of Belleville, Illinois.
Hodgkinson died of his injuries, President Donald Trump said in his address to the country.
"Many lives would have been lost if not for the heroic actions of the two Capital Police officers," President Trump said of Virginia shooting.
"Always remember those who serve and keep us safe," he said.
U.S. House Republican, Steve Scalise of Louisiana, was shot by a rifle-wielding gunman Wednesday at that practice just outside of Washington. At least four other people were also shot.
An initial police report lists the gunman's weapon as an M-4 assault weapon, CBS News has learned.
Hodgkinson's Facebook page contains anti-Trump statements:
"Trump is a Traitor. Trump Has Destroyed Our Democracy. It's Time to Destroy Trump & Co."
His Facebook page also shows a photo of Democratic Senator Bernie Sanders. Sanders said Hodgkinson apparently volunteered on his presidential campaign.
Sanders, of Vermont, said in a statement: “I am sickened by this despicable act.”
He says that “violence of any kind is unacceptable in our society and I condemn this action in the strongest possible terms.”
Senator Jeff Flake, R-Arizona, described the gunman to reporters as a middle-aged white male wearing a blue shirt and possibly jeans.
"My view of him was just quick behind the dugout, and then when I realized he had a line of sight into the dugout with all the members there then we obviously went back down quickly," Flake said.
Capitol Police said officers who were part of Scalise's security detail returned fire and wounded the shooter, who was taken into custody.
"This is a stable situation," Michael Brown, chief of police for Alexandria, Virginia, told reporters. "At this point, there's no additional threat. We consider this incident to be a closed incident under investigation."
Scalise was shot in the hip, his office said in a statement. He was undergoing surgery at a hospital and was in stable condition. Before surgery, he spoke to his wife on the phone and was in good spirits, the statement said.
House Speaker Paul Ryan addressed the House after the Virginia shooting.
"We are united in our anguish. An attack on one of us is an attack on all of us," Ryan said.
The Associated Press contributed to this report.