A suicide expert witness can explain causes of murder-suicde to a jury. The motivation for the murder in murder-suicide can be purely criminal in nature or be perceived by the perpetrator as an act of care for loved ones in the context of severe depression. The severely depressed person may see the world as a terrible place and can feel that they are helping those they care about by removing them from it. Thoughts like this are generally regarded as a medical emergency requiring suicide intervention.
Since crime just prior to suicide is often perceived as being without consequences, it is not uncommon for suicide to be linked with homicide. Motivations may range from guilt to evading punishment, insanity, part of a suicide pact, or exacting revenge on those whom they feel are responsible.