Subject is exactly Pierre Salinger
Reporters have worked as guards or gotten themselves arrested -- sometimes with the aid of authorities and sometimes without -- to investigate conditions inside prisons and jails.
San Francisco Chronicle prisons investigation involving undercover as a prisoner by Tim Findley and as a guard by Charles Howe.
Arizona Daily Star reporter R.H. Ring spent 10 days posing as a maximum-security convict at Arizona's Florence State Penitentiary. Very few people in the prison system knew of his stay, not even Florence's warden.