A 30-year minimum should also apply to the worst single murders, including those with sexual or racial motives and the use of a firearm - until 2015, the murder of a police officer in the course of duty also came within this category. Most other murders should be subject to a 15-year minimum as a starting point. There have been numerous departures from these guidelines since they were first put into practice. For example, the judge who sentenced American fugitive David Bieber for the murder of a police officer said that he should never be released from prison, whereas statutory guidelines recommended a 30-year minimum for this type of murder - this was a decade before the act was amended to include the murder of a police officer in the course of duty as one of the offenders whose life sentences should mean life.