An early morning practice for a Congressional charity baseball game erupted in gunfire in Alexandria, Virginia, on Wednesday, when an Illinois man armed with a semiautomatic rifle began firing at Republican lawmakers and staffers as they took batting practice.

Representative Steve Scalise of Louisiana, the House majority whip, was shot in the hip as he stood on second base. Witnesses said he then crawled into the outfield, leaving behind a trail of blood. As of Thursday morning, he remained in critical condition.

Two Capitol Police officers, a lobbyist, and a congressional staffer were also wounded. The lobbyist, Matt Mika, was also in critical condition as of Thursday morning.

The gunman, identified as James Hodgkinson, a 66-year-old from Belleville, Illinois, was shot after what witnesses described as a 10-minute exchange with the wounded Capitol Police officers and Alexandria Police. He later died.

Speaking to reporters after the shooting, Representative Mo Brooks of Alabama described hearing between 50 and 100 shots ring out across the park during batting practice. Hodgkinson, armed with a rifle, fired from behind the dugout, witnesses said.

“There was so much gunfire, you couldn’t get up and run,” Representative Mike Bishop of Missouri told the New York Times. “Pop, pop, pop, pop — it’s a sound I’ll never forget.”

Senator Rand Paul of Kentucky hailed the quick response by Scalise’s protective detail. “It would have been a massacre without them,” he said.

Scalise is the third-highest ranking House Republican, and has an around-the-clock security detail. Speaking from the White House, President Donald Trump described the attack as a “very, very brutal assault.”

An FBI agent told the Associated Press that it was “too early to say” whether the shooting was a targeted attack. Hodgkinson was highly critical of President Trump and Republican leaders in general on his social media accounts. According to Politico, he volunteered with the Bernie Sanders campaign during the 2016 election.

The lawmakers and their aides had assembled on the baseball diamond to practice for an annual showdown between Democrats and Republicans. House Speaker Paul Ryan announced that the popular event will proceed as scheduled on Thursday night at Nationals Park across the Potomac River in Washington.

“We are united. We are united in our shock, we are united in our anguish,” Ryan said on the House floor, before receiving a bipartisan standing ovation. “An attack on one of us is an attack on all of us.”

Here’s what we know, and still don’t know, about the attack.

The gunman had been arrested for battery, but likely was not prohibited from gun ownership

In April 2006, Hodgkinson was accused of forcing his way into the bedroom of a neighbor’s house in order to fetch his daughter. When she refused to leave, a fight broke out, according to a report from the St. Clair County, Illinois, sheriff’s office. The report, which is based on witness testimony, describes what happened next: Hodginkson threw his daughter to the floor, hitting her arms and legs. When his daughter and her friend tried to escape in a green Honda Civic, Hodgkinson reached inside the door and cut the seat belt with a pocketknife. The friend’s boyfriend later went to Hodgkinson’s house to speak about the encounter. Hodgkinson confronted him with a shotgun. The boyfriend ran away and Hodgkinson discharged the firearm.

Hodgkinson was charged with domestic battery and discharging a firearm. Had he been convicted on the battery charge, he would have been prohibited from owning guns under Illinois law.

In the police report, Hodgkinson is also alleged to have choked his daughter as she clung to the steering wheel of a car.

Melissa Jeltsen, who covers domestic violence for HuffPost, has reported that strangulation is seen as a strong predictor of future violence. If a woman has been choked by an intimate partner, she is seven times more likely to become a homicide victim in the future.

The charges against Hodgkinson stemming from the 2006 incident were dismissed. It wasn’t immediately clear why. Four years later, in 2010, Illinois made it a felony to choke or strangle a person during a domestic battery.

On March 24 of this year, sheriff’s deputies were called to an area near Hodgkinson’s house after neighbors reported hearing about 50 gunshots. The deputies found Hodgkinson with a hunting rifle. But because he had a valid Illinois firearms license and was in a part of the county where shooting was not illegal, the deputies told him to be mindful of the homes in the area and left.

Law enforcement recovered two weapons at the scene, including a semiautomatic rifle

Mary Markos, a spokeswoman for the Bureau of Alcohol, Tobacco, Firearms and Explosives, said the agency is tracing two firearms recovered at the scene: one rifle and one handgun.

The ATF is prohibited from releasing details of firearms traces, including make, model, and who originally purchased or sold the weapon, to anyone except the law enforcement agency who requested the trace.

The shooter likely brought his weapons from out of state

Hodgkinson was a resident of Illinois, and had only been living in Virginia for a few weeks. Federal law allows for the purchase of guns in another state — either through a private sale or from a licensed dealer — but buyers must take possession of the firearm in their state of residence.

As a result, it is most likely that he acquired the weapons used in the attack in Illinois. The Chicago Tribune reports that Hodgkinson had purchased at least three firearms from a local gun shop over the past few years.

Anyone wishing to possess a firearm in Illinois must obtain a Firearm Owners ID from the State Police. Applicants must pass a background check and pay a $10 fee. Sales between private parties do not require a background check. However, both the seller and buyer must have an ID card.

Gun sales in Illinois are also subject to waiting periods. Residents who purchase a handgun must wait 24 hours to receive the weapon. The waiting period for rifles and shotguns is 72 hours.

The lawmakers targeted in the attack were staunch supporters of the Second Amendment

Scalise is a fierce defender of gun rights, and maintains a grade of A+ from the National Rifle Association.

During the presidential transition, Saclise served on Trump’s Second Amendment Coalition, a group whose broadly defined purpose was to “protect our Supreme Court and our right to keep and bear arms.” Over the course of his nearly decade-long tenure, he has sponsored or co-sponsored legislation that would ease restrictions on the sale of firearms and allow permit-holding gun owners to carry concealed weapons anywhere in the country. In an interview last year, he called the Second Amendment “sacred to our nation’s founding.”

Representative Brooks, who gave a harrowing firsthand account of this morning’s shooting, is also an avid gun-rights proponent. He has a concealedcarry permit and has headlined events celebrating the Second Amendment.

The shooting, Brooks said today, has not changed his views on the issue. “The Second Amendment right to bear arms is to ensure that we always have a republic,” he said. “And as with any Constitutional provision in the Bill of Rights, there are adverse aspects to each of those rights that we enjoy as people.”

He added, “But we’re not going to get rid of speech because some people say some really ugly things that hurt people’s feelings.”

Scalise is the first sitting member of Congress to be shot since 2011

Six years ago, Representative Gabrielle Giffords of Arizona was critically wounded at a Congressional meet-up in Tucson. Six people, including a federal judge and a 9-year-old girl, died in the attack.

A total of 17 members of Congress have been shot while in office. Here are four of the most recent incidents:

  • In 1978, Representative Leo Ryan of California was fatally shot while on a fact-finding mission to the Jonestown commune in Guyana.
  • In 1973, Senator John Stennis of Mississippi was shot and wounded during a robbery in front of his Washington, D.C., home.
  • In 1968, Senator Robert Kennedy of New York was fatally shot on the presidential campaign trail in Los Angeles.
  • In 1954, five members of Congress — Alvin Bentley, Clifford Davis, George Fallon, Ben Jensen, Kenneth Roberts — were wounded when four Puerto Rican nationalists opened fire on the House floor.