Corrected entry: In the US (and most other places) ex-police officers and prison guards who are sentenced to a term of imprisonment are never, ever put into the general prison population - they are always put into protective segregation. There are no exceptions and the prisoner cannot request that they be not segregated - it just does not happen.
brianjr0412
8th Aug 2014
Correction: This is a persistent urban myth, and it is wrong. If possible an ex-police officer or prison guard will be incarcerated in another state, well away from the scene of the crime. If that isn't possible they can request they be assigned to Administrative Segregation but they do not have to. They can request they be admitted to the general prison population, and most do. Drew Walter Peterson (look him up) probably wishes he hadn't as he got clobbered by a disgruntled inmate wielding a meal tray.
A better example is that of Michael Rudkin, a former corrections officer sentenced to 10 years for having sex with a female inmate. He tried to hire an inmate to arrange the murder of his ex-wife, the female inmate, his ex-wife's boyfriend and the federal investigator prosecuting him. He had ninety years added to his sentence. In August 2004 he tried to arrange the murders again, and this time the inmate he approached responded by beating him to death.