The shooting suspect was identified as Cole Tomas Allen, 31, of Torrance, California, two law enforcement officials told the AP. Officials told reporters after the incident that Allen was armed with a shotgun, a handgun and multiple knives.

Security for the annual event is always tight when the president attends, especially given the venue’s history — 45 years ago, the Washington Hilton was the site of an attempted assassination of President Ronald Reagan — and law enforcement argued that their “multi-layered protection” worked as designed. Still, the incident was sure to set off more questions about security around the president and political events in the wake of high-profile acts of political violence in recent years.

Here’s what we know about the security of the correspondents’ dinner.

The perimeter at the Washington Hilton

The interim police chief for Washington’s Metropolitan Police Department, Jeffery Carroll, told reporters Saturday evening that investigators believe that the suspect was staying in the hotel and that appears to be how he was able to enter the hotel at the time of the event.

The hotel was closed to the public beginning at 2 p.m. Saturday in anticipation of the dinner which began at 8 p.m. Outside, dozens of protesters gathered in the rain — mostly directing their criticism at the media attending the event.

Access to the hotel was restricted to hotel guests, people with tickets to the dinner itself, an invitation to one of the receptions that are held at the hotel before or after the dinner, or documents from the White House Correspondents’ Association indicating affiliation with the dinner.

The 2,300 guests at the event in the hotel’s cavernous subterranean ballroom had to pass through several additional checks to enter the room, including showing tickets to association volunteers and hotel staff and passing through magnetometers manned by the Secret Service and Transportation Security Administration.

It was not immediately released when the suspect checked into the hotel. Security camera footage released by Trump to social media shortly after the incident shows the gunman running past security officers who appear to be disassembling the metal detectors. Once the president was seated in the ballroom, additional attendees were not permitted to enter the secured area, which is why they were taking them down.

“It shows that our multi-layered protection works,” Secret Service director Sean Curran said. His comments were echoed by Carroll, who said the security plan for the evening was developed by the Secret Service and “that security plan did work this evening.”

Security measures inside the ballroom

Inside the ballroom for the dinner itself there were further security measures.

The U.S. Secret Service maintained another perimeter around the president that included a buffer separating him and others seated at the head table from the rest of the attendees. Armored plates were hidden under the table where Trump was seated. Secret Service agents were at their posts in front of the stage and in its wings, as were heavily armed counter-assault agents ready to respond to threats. Security details for dozens of other high-profile attendees were also in the ballroom.

A spokesperson for the hotel directed questions about their security measures to the U.S. Secret Service.

Assassination attempt of Reagan at the Washington Hilton

The hotel itself has a long presidential history, and everyday people have regularly booked rooms or filled the lobby bar to watch people at an event that attracts Washington’s elite and has also drawn celebrities like George Clooney and Kim Kardashian as well as hosts including Jimmy Kimmel and Trevor Noah.

Although known for the correspondents’ dinner, the hotel regularly hosts large events in the nation’s capital, especially those that feature the president. It was the site of the shooting of Reagan by John Hinckley Jr. on March 30, 1981.

Reagan was returning to his limousine after a speaking engagement when Hinckley shot him with a revolver, seriously wounding him. Hinckley believed the attack would impress the actress Jodie Foster.

Security overhauls and US Secret Service training

After that incident, the hotel built extensive security modifications specifically to accommodate the president, including a secured garage designed to fit the presidential limo which leads to a dedicated elevator and staircase to ferry them to a secured suite reserved for their personal use.

The suite includes a reserved bathroom that the hotel traditionally adorns with monogrammed towels for the president for the handful of times they are in the space every year.

Because of the venue’s long presidential history, the Secret Service has long used the annual event to put some agents through their paces because the venue has been extensively studied by the agency for decades.

However, since the 2017 mass shooting in Las Vegas, many major hotels have also tightened security protocols, in some cases adopting measures such as periodic room checks or policies aimed at flagging extended privacy requests. It was not immediately clear when the person involved Saturday checked into the hotel, or whether any such measures would have had any bearing in this case.