U.S. Senator Bernie Sanders speaks at a Our Revolution rally in Boston, Massachusetts, U.S., March 31, 2017. Mary Schwalm/REUTERS

The gunman who opened fire on a Republican congressman and others Wednesday morning at a baseball field in Alexandria, Virginia, had expressed hatred for Republicans on social media and was a strong supporter and volunteer for Democrat Sen. Bernie Sanders' presidential campaign.

James T. Hodgkinson, a 66-year-old owner of a home inspection business in Belleville, Illinois, was identified as the shooter. He specifically targeted the Republican team as they practiced for an annual charity baseball game. Injured in the attack were Steve Scalise, Majority Whip of the House of Representatives, two members of Scalise’s protective detail, a congressional aide and a lobbyist.

In a White House statement, President Trump confirmed Hodgkinson had died from injuries sustained in the shootout.

Sanders was quick to condemn the actions of Hodgkinson, whose Facebook page features pictures of the Vermont politician.

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"I have just been informed that the alleged shooter at the Republican baseball practice is someone who apparently volunteered on my presidential campaign," Sanders announced on the Senate floor. "I am sickened by this despicable act. Let me be as clear as I can be, violence of any kind is unacceptable in our society and I condemn this action in the strongest possible terms.”

According to the Washington Post, Hodgkinson has had brushes with the law, including being charged with assault and battery in April 2006 in an incident that also included him aiming a shotgun at the person he allegedly punched. The charges were later dismissed.

"Trump is a Traitor. Trump Has Destroyed Our Democracy. It's Time to Destroy Trump & Co.,” Hodgkinson posted on his Facebook wall in March. He posted in February: "Republicans are the Taliban of the USA.”

Sanders called for moving forward peacefully.

“Real change can only come through nonviolent action, and anything else runs against our most deeply held American values,” Sanders continued in his statement. “My hopes and prayers are that Representative Scalise, congressional staff and the Capitol Police Officers who were wounded make a quick and full recovery. I also want to thank the Capitol Police for their heroic actions to prevent further harm.”

Congress struck a rare tone of unity with members of both parties calling for peace after the violent act.

“An attack on one of us is an attack on all of us,” said Republican Speaker of House Paul Ryan in a statement to the House of Representatives. “There are so many memories from this day that we will want to forget, and there are so many images we will not want to see again. But, there is one image, in particular, that this House should want to keep … a photo I saw this morning of our Democratic colleagues gathered in prayer after hearing the news.”

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Democratic House Minority Leader Nancy Pelosi also addressed the House.

“To my colleagues, you’re going to hear me say something you’ve never hear me say before, I identify myself with the remarks of the speaker,” said Pelosi. “We are not one caucus or the other in this House today, we speak for each other in saying that we send out thoughts and our prayers to our colleague Steve Scalise.”