WASHINGTON (AP) — In many ways, the assassination attempt against Donald Trump at a Pennsylvania campaign stop was a perfect storm of failings coming together that allowed 20-year-old Michael Thomas Crooks to climb on top of a nearby building and take eight shots at the once and future president.

One attendee was killed, two others wounded and a bullet grazed Trump’s ear before a Secret Service counter sniper opened fire on Crooks and killed him.

It also became a turning point for the agency tasked with protecting the president. As more details emerged about what went wrong, questions multiplied: What happened to the Secret Service’s planning? Why was a rooftop with a clear line of sight to Trump left unguarded? What motivated the shooter?

Another incident in September where a gunman camped in the shrubbery outside one of Trump’s golf courses before being spotted and shot at by a Secret Service agent also raised questions about the agency’s performance.

A year after Butler, multiple investigations have detailed the breakdowns that day. Under a new leader hired by Trump, the agency has been pushing to address those problems but key questions remain.

“This was a wake-up call for the Secret Service,” said retired supervisory agent Bobby McDonald, who’s now a criminal justice lecturer at the University of New Haven.

A Senate committee and federal auditing agency over the weekend released reports about the Secret Service’s actions.

All the investigations zeroed in on a few specific problems.

The building with a clear sight line to the stage where the president was speaking only 157 yards away was left unguarded. Crooks eventually boosted himself up there and fired eight shots with an AR-style rifle.

The Secret Service’s investigation into its own agency’s conduct said that it wasn’t that the line-of-sight risks weren’t known about ahead of time. It was that multiple personnel assessed them as “acceptable.”

Supervisors had expected large pieces of farm equipment would be situated to block the view from the building. Those ultimately weren’t placed, and staffers who visited the site before the rally didn’t tell their supervisors that the line-of-sight concerns hadn’t been addressed, the report said.

Another glaring problem: fragmented communications between the Secret Service and the local law enforcement that the agency regularly relies on to secure events.

Instead of having one unified command post with representatives from every agency providing security in the same room, there were two command posts at the rally. One investigation described a “chaotic mixture” of radio, cell phone, text, and email used to communicate that day.

And a year later, the investigations are still coming.

“There were multiple, unacceptable failures in the planning and execution of the July 13 Butler rally,” said the Senate Committee on Homeland Security & Governmental Affairs in a report released Sunday.

The committee found that the agency denied “multiple requests for additional staff, assets, and resources to protect President Trump” during the presidential campaign. The committee said that included at least two requests for the Butler rally.

The agency’s former director, Kim Cheatle, last year told a House panel before she resigned that the agency didn’t deny any requests for the rally.