A Georgia man who had blamed the COVID-19 vaccine for making him depressed and suicidal has been identified as the shooter who opened fire late Friday on the U.S. Centers for Disease Control and Prevention headquarters, killing a police officer.

The 30-year-old suspect, who died during the attack, had also tried to get into the CDC’s headquarters in Atlanta but was stopped by guards before driving to a pharmacy across the street and opening fire, a law enforcement official told The Associated Press on Saturday.

The man, identified as Patrick Joseph White, was armed with five guns, including at least one long gun, the official said, speaking on condition of anonymity because of not being authorized to discuss the investigation publicly.

A union representing workers at the CDC said the shooting was not random and “compounds months of mistreatment, neglect, and vilification that CDC staff have endured.” It demanded federal officials condemn vaccine misinformation, saying it was putting scientists at risk.

Here’s what to know about the shooting and the continuing investigation:

Police say White opened fire outside the CDC headquarters in Atlanta on Friday, leaving bullet marks in windows across the sprawling campus. At least four CDC buildings were hit, Director Susan Monarez said on X.

DeKalb County Police Officer David Rose was fatally wounded while responding. Rose, 33, a former Marine who served in Afghanistan, had graduated from the police academy in March.

White was found on the second floor of a building across the street from the CDC campus and died at the scene, Atlanta Police Chief Darin Schierbaum said. The police chief added that “we do not know at this time whether that was from officers or if it was self-inflicted.”

The Georgia Bureau of Investigations said the crime scene was “complex” and the investigation would take “an extended period of time.”

The American Federation of Government Employees, Local 2883, said the CDC and leadership of the Department of Health and Human Services must provide a “clear and unequivocal stance in condemning vaccine disinformation.”

Such a public statement by federal officials is needed to help prevent violence against scientists, the union said in a news release.

“Their leadership is critical in reinforcing public trust and ensuring that accurate, science-based information prevails,” the union said.

Fired But Fighting, a group of laid-off CDC employees, has said HHS Secretary Robert F. Kennedy Jr. is directly responsible for the villainization of CDC’s workforce through “his continuous lies about science and vaccine safety, which have fueled a climate of hostility and mistrust.”

Kennedy reached out to staff on Saturday, saying “no one should face violence while working to protect the health of others.”

In a statement provided Monday, HHS Communications Director Andrew Nixon said Kennedy “has unequivocally condemned the horrific attack and remains fully committed to ensuring the safety and well-being of CDC employees.” Nixon added that Rose’s “sacrifice to protect the CDC on its darkest day will never be forgotten.”

Thousands of people who work on critical disease research are employed on the campus. The union said some staff were huddled in various buildings until late at night, while more than 90 young children who were locked down inside the CDC’s Clifton School.

The union said CDC staff should not be required to immediately return to work after experiencing such a traumatic event. In a statement released Saturday, it said windows and buildings should first be fixed and made “completely secure.”

“Staff should not be required to work next to bullet holes,” the union said. “Forcing a return under these conditions risks re-traumatizing staff by exposing them to the reminders of the horrific shooting they endured.”

The union also called for “perimeter security on all campuses” until the investigation is fully completed and shared with staff.

White’s father contacted police and identified his son as the possible shooter. The father said his son had been upset over the death of his dog and also had become fixated on the COVID-19 vaccine, according to the law enforcement official.

A neighbor of White’s told The Atlanta Journal-Constitution that White “seemed like a good guy” but spoke with her multiple times about his distrust of COVID-19 vaccines in unrelated conversations.

“He was very unsettled, and he very deeply believed that vaccines hurt him and were hurting other people,” Nancy Hoalst told the Atlanta newspaper. “He emphatically believed that.”

But Hoalst said she never believed White would be violent: “I had no idea he thought he would take it out on the CDC.”