A former Minneapolis police officer says a code of silence encourages unethical even criminal behavior among some cops. And, Michael Quinn says, the code of silence encourages good cops to say nothing to prevent the bad behavior of other police officers. Quinn has written a book titled, "Walking With the Devil, The Police Code of Silence." He says it has angered some former colleagues. But he and others say the problem is pervasive and tempts some police to take the law into their own hands. Quinn remembers he was two months into his job as a Minneapolis police rookie when he had his first encounter with the code of silence. It was 23 years ago. He and his training officer were walking the beat on Hennepin Avenue in downtown Minneapolis when the older officer said he had a job on the side while he was on duty. He told Quinn to come along and offered some of the cash. Quinn says he declined the money, and when he asked fellow officers what to do they told him to ignore it.