No matter how helpful a confidential informant is, some of them will always return to bad habits. Duluth News Tribune reports today that drug informant Paul Kastern has been jailed for five years for selling methamphetamine. Since the 1980s, Kastern has helped police convict other drugs offenders in return for having his own sentences reduced. He even helped to convict his own attorney of snorting cocaine and smoking marijuana. However, in February 2009, Kastern was caught out when another confidential informant purchased meth from him on three separate occasions.