Greetings everybody!
We often see very prolific murderers and criminals, who, when they are brought to the court of law, defend themselves by saying they acted upon religious instincts, that their "gods" told them to act so and so for a said divine purpose. How can we use our knowledge of forensic psychology to counter such beliefs and are these people considered mentally sick and in need of psychiatric help or are they criminals who acted on their own will and are guilty of every crime they commit?
Belief that a god told them to commit a crime is widely delusional and a sign of mental illness. There are likely people who malinger on delusions and hallucinations to attempt to get out of trouble, but that's where psychological testing comes in handy.