The man who fired more than 500 rounds at the US Centers for Disease Control and Prevention appears to have tried to get onto the agency’s campus two days before the August 8 shooting, according to an agency email obtained by CNN.

The shooter, identified by authorities as Patrick Joseph White, appears to have been captured in security camera footage trying to enter the campus visitor’s center late in the afternoon on Aug. 6, according to an internal email to CDC staff, reviewed by STAT. The email said “the likelihood is very high” the person in the video is White.

The letter sent to agency employees and reviewed by ABC News says there is a “very high likelihood” that Patrick Joseph White, 30, tried getting onto the CDC campus two days before the shooting.