In the group, current and former Border Patrol agents joked about the death of migrants, posted vulgar images of Alexandria Ocasio-Cortez, and shared racist memes.
Under President Barack Obama the agency was under the microscope for reform, but under the Trump administration any progress toward that goal has been halted.
The postmortem by Michael Baden is only the beginning as teams of specialists study the body of an 18-year-old African American killed by police in Ferguson, Missouri.