On November 7, 2003, Singleton was sentenced to life in prison without the possibility of parole. He had been convicted of murder and aggravated mayhem the previous June after pleading not guilty by reason of insanity at the time of the murder. The defense argued that Singleton was in a psychotic state due to his use of PCP the night before the murder. The court ruled that his intoxication and claimed insanity were not satisfactory reasons for committing the crime. The district attorney argued that drug use can not be used as grounds for an insanity plea in California, and the judge agreed.