Four police officers have resigned after an investigation revealed they had offered remand prisoners favours in return for confessions.
Prisoners were allowed to have sex with their girlfriends, take home visits and were given cigarettes and extra meals.
Bedfordshire Police confirmed on Monday that three officers were required to resign. A fourth resigned voluntarily.
Operation Bedouin revealed some of the prisoners admitted to some crimes that took place when they were in jail.
As a result of the officers' actions, the crime detection rate improved in Luton.
Bedfordshire Deputy Chief Constable Martin Stuart told BBC News: "Following the identification of irregular crime recording practices at Luton, Bedfordshire Police has conducted a detailed internal investigation ending with a misconduct hearing in May 2006.
"As a result of the investigation, one officer has voluntarily resigned from the force, three others have been required to resign and one fined a total of 10 days' pay and reprimanded."
Mr Stuart added: "The honesty and integrity of our staff is vital to public confidence. Where these standards are compromised, we will and do take positive steps to deal with staff who have acted against our strict code of conduct."
The force has refused to release the names of the four officers.
Bedfordshire Police Federation, which represents the force's rank-and-file officers, declined to comment.