Ex-lieutenant pleads guilty in federal court ...
"Cellmate on cellmate" violence ...
"Prison Empire" nabs more than fifty defendants ..
Advocates want to let the sunlight in ...
Operation targeted military personnel ...
Prison officials do not suspect foul play ...
Incidents unrelated, not connected to violence ...
Federal, state officials team up for test ...
U.S. attorney for South Carolina makes her case ...
Punishments need to start fitting crimes ...