The CDC has tightened security following an attack Friday on its Atlanta headquarters that left a police officer and the gunman dead, including having employees work from home on Monday and removing vehicle decals showing where they work.

The union representing workers at the U.S. Centers for Disease Control and Prevention said the violence “compounds months of mistreatment, neglect, and vilification that CDC staff have endured,” citing reports that the gunman blamed the Covid-19 vaccine for making him depressed and suicidal.

Since being named Health and Human Services Secretary earlier this year, Robert F. Kennedy Jr. has targeted vaccine policy, and in May withdrew a federal recommendation for Covid shots for pregnant women and healthy children.

Kennedy will visit the CDC campus in Atlanta on Monday, according to a source familiar with the plans.

“No one should face violence while working to protect the health of others,” Kennedy Jr. said in a post on X on Saturday.

A source briefed on the matter told Reuters that 189 rounds of gunfire had hit the CDC buildings during the attack, 85 windows were broken and over 100 doors destroyed, among other damage.

The Atlanta Police Department referred calls to the Georgia Bureau of Investigation, which did not have an immediate comment.

Both local and federal law enforcement are “conducting intensive monitoring of all potential threats to CDC and its staff,” the agency’s acting Chief Operating Officer Christa Capozzola said in an email to staff over the weekend that was seen by Reuters.

She said work was under way to clean up and repair extensive damage to the CDC’s campus by the shooter who, according to the investigation so far, acted alone.

An “all-staff” meeting on Tuesday will become a virtual-only event, CDC Director Susan Monarez said in a separate email to employees seen by Reuters. She said teams were working hard to determine “our workplace posture” moving forward.

The agency’s safety division asked employees to remove CDC-identifying decals from their vehicles, an email seen by Reuters showed.

(Reporting By Deena Beasley and Dan Levine in San Francisco; Additonal reporting by Rich McKay in Atlanta; Editing by Bernadette Baum)