Colleagues of both described their previous relationship as strong and friendly, though they have not worked together.
Colleagues at the hospital described him as a reliable medical professional whose other interests were private.
A colleague once described him as having a "case of terminal responsibility."
One former colleague described her as "a bull in the china shop" at times.
Colleagues and others have described them as quiet, gentle professionals who kept to themselves.
But in the journal article, he and his colleagues described the vaccine experiment.
As his friends and colleagues describe him, Landis has two sides.
Colleagues described him as a determined salesman who thought that more than five hours of sleep a night was a waste.
Colleagues and former employees described him as a shrewd entrepreneur.
His colleagues there later described him a private person with some odd behaviours.