ATLANTA (AP) — A man who unleashed over 180 gunshots at the U.S. Centers for Disease Control and Prevention’s headquarters obtained his father’s firearms by breaking into a locked safe, authorities stated Tuesday. He allegedly intended to protest against COVID-19 vaccinations.

The Georgia Bureau of Investigation Director, Chris Hosey, noted that materials uncovered at the residence of Patrick Joseph White, where he resided with his parents, showed his unhappiness with COVID-19 vaccines.

White, 30, had written about wanting to make “the public aware of his discontent with the vaccine,” Hosey said.

White reportedly had vocalized thoughts of suicide recently, which had previously alerted law enforcement to the situation weeks before the incident. He died by suicide at the scene last Friday after fatally shooting a police officer.

FBI Special Agent Paul Brown stated on Tuesday that although they’ve not noticed an increase in threats based on misinformation concerning the CDC and its vaccination efforts, any language inciting or leading to violence is taken with utmost seriousness.

“Although we are tracking it, we are sensitive to it, we have not seen that uptick,” said Brown, who leads the FBI’s Atlanta division.

Authorities reported that White’s family was cooperating fully with the ongoing investigation. White did not have any known prior criminal record, according to Hosey.

Authorities executed a search warrant at the family’s Kennesaw home, where they retrieved written materials now under analysis and electronic devices currently being forensically examined.

Investigators also recovered a total of five firearms, including a gun that belonged to his father that he used in the attack, Hosey said.

Hosey said the suspect did not have a key to the gun safe: “He broke into it,” he said.

White had been stopped by CDC security guards before driving to a pharmacy across the street, where he opened fire from a sidewalk, authorities said. The bullets pierced “blast-resistant” windows across the campus, pinning employees down during the barrage. More than 500 shell casings have been recovered from the crime scene, the GBI said.

In the aftermath, officials at the CDC are assessing the security of the campus and making sure they notify officials of any new threats.

U.S. Health Secretary Robert F. Kennedy Jr. toured the CDC campus on Monday, accompanied by Deputy Secretary Jim O’Neill and CDC Director Susan Monarez, according to a health agency statement.

“No one should face violence while working to protect the health of others,” Kennedy said in a statement Saturday. It said top federal health officials are “actively supporting CDC staff.”

Kennedy also visited the DeKalb County Police Department, and later met privately with the slain officer’s wife.

A photo of the suspect will be released later Tuesday, Hosey said, but he encouraged the public to remember the face of the officer instead.

Kennedy was a leader in a national anti-vaccine movement before President Donald Trump selected him to oversee federal health agencies, and has made false and misleading statements about the safety and effectiveness of COVID-19 shots and other vaccines.

Some unionized CDC employees called for more protections. Some employees who recently left the agency as the Trump administration pursues widespread layoffs, meanwhile, squarely blamed Kennedy.

Years of false rhetoric about vaccines and public health was bound to “take a toll on people’s mental health,” and “leads to violence,” said Tim Young, a CDC employee who retired in April.