Could someone who is insane commit murder?

Yes, someone who is considered insane can commit murder. Legal standards for insanity vary by jurisdiction, but in many cases, a person may be found not criminally responsible if they were unable to understand the nature of their actions or distinguish right from wrong due to their mental illness. However, this does not mean that individuals with mental health issues are inherently violent; most people with mental illnesses are not violent and do not commit crimes.