In a large and hastily arranged Zoom call on Saturday, about 800 rattled staffers with the US Centers for Disease Control and Prevention tried to make sense of the trauma they endured just a day earlier when a gunman opened fire on the agency’s buildings from across the street.

The CDC, which tracks outbreaks of illness in the US, played a central role during the Covid pandemic and has been heavily-criticised by vaccine sceptics. Officer Rose was a former Marine who had served in Afghanistan.

The suspected gunman in the attack that killed a police officer near the Emory University campus and the CDC's headquarters was identified Saturday morning.